I thought that I’d start off the day with a nod to the reader responses I’ve been getting for this project.  It’s really nice to see the reactions that are coming in here, and there have been some good ideas and suggestions.  
From Erik –

I’ve only been following this site for a short while, but I really look forward to this series. I enjoy deck building advice that includes theory style advice. Examples are great, but advice about how to determine path that has synergy with a general is excellent. Any advice about how to make a deck more than the sum of its parts is definitely something to look forward to.
Thanks, Erik.  I appreciate the comment in a big way.  The key to a successful EDH build is all about the synergy – I’m happy to repeat that until I’m completely blue in the face.  With all of the new EDH-centric product hitting the market, the format is enjoying more players that ever, and I want to show as many people as I can that 99-card casual decks can benefit from proper design and attention to card advantage as much as a Standard or Eternal deck can.  
From Zach –

I was gonna say that Xiahou Dun and Toshiro Umezawa seem like a tag team made in heaven…I think you want Umezawa as general, and then you use Xiahou Dun to recur the permanents/sorceries you need (Grave Pact, Demonic Tutor etc.) to keep Umezawa satisfied with flashback triggers. Maybe even add in a Morbid sub-theme!
To be honest, I’m kind of surprised I managed to gloss over Toshiro until now.  With the correct build, it seems like he could be an incredible card-advantage engine.  
In this case, though, I feel like Xiahou Dun is occupying the same space Toshiro does, with a slightly higher mana cost, but a far-reaching advantage in what comes back from the yard.  If Toshiro let you play the card without playing its mana cost, I might reconsider a bit.  But in this case, All I need to do is put Xiahou Dun into play to regrow anything black.  I don’t have to be limited to instants, and I don’t have to wait for a opponent’s creature to kick off first.
Morbid is going in either way, though.  A few of you pointed out how strong it is here, and you’re spot-on.
From Dave-

Every creature is both synergistic and a lightening rod….you can overwhelm removal between drawing a million questions and using reanimation spells + Xiahou to keep bringing them back. not a graveyard deck.
It’s really difficult to force myself to back down from running every cool black creature I can get my hands on, but you’re correct – the creature additions need to serve a purpose and drive the synergy of the deck.  I’ll be focusing very heavily on the engines that the deck can create to gain advantage – how does it work with itself to draw cards?  How can it handle removal, and deploy removal of its own?  How does it win?
To that end, I think it makes sense to leverage some reanimation, but I want to be careful about how heavily the deck focuses on the graveyard.  Xiahou Dun already throws it heavily in that direction and I don’t want to be dead in the water to concentrated grave hate – hence the focus on sacrifice mechanics.
From Chad

I built a mono black Voltron Xiahou dun EDH when the judge foil became mildly affordable…It did a lot better than I expected with the use of bonehoard, hatred, strata scythe, lashwrithe and like to push out massive damage…Quietus spike also goes well with the Unblockable ability. Also some self-recursive creatures would be useful with all the sac outlets and grave pact effects. Gate to phyrexia is always useful in mono black as a artifact removal spell.
Did I short-sell the Voltron route on my last post?  It seems like a lot of you are replying with similar sentiments here, and these are some good options.  Here’s a question I’d like to see some replies to in the ‘Comments’ section:
-Given that I don’t want to go with Poison/Infect, and that my playgroup does not use general damage, should I still consider going the Voltron route?
I’m all for changing course if it makes sense, but I’ll admit that I don’t really see the path personally.  I’m perfectly willing to build the list out in this direction for other purposes – for example, to take to GenCon with.  What do you all think?
Gate To Phyrexia is spot-on, by the way.  Added to the list.  Wish there was an enchantment version…
From Imshan-

Since a bunch of graveyard hate is in the form of artifacts with activated abilities, Null Rod is way of stopping the usual crud like Tormod’s Crypt or Relic of Progenitus.
Between this and Witchbane Orb, the door closes on quite a bit of grave hate.  This clearly provides problems if I shift gears and head toward equipment-based aggro, but I think it might be a must-include in the current direction.
Erik, Part 2-  

I think for the sacrifice theme, you should consider Moriok Replica, and definitely Butcher of Malakir. Also, in mono black with an self-sacrificing general: Sword of Light and Shadow is going to be awesome…Have you considered Staff of Nin for painless drawing and some damage too?

I tend to not get too excited about SoLS.  The lifegain isn’t completely inconsequential, though, nor is the creature return.  It does fly at odds with using Xiahou Dun for his ability, but the flexibility is worth looking at.  This is a slam-dunk if the Voltron route is the better option.
I’m not sold on Staff of Nin yet.  Is six mana too much to pay for a one-sided Howling Mine in this deck?  Black isn’t hurting for good card draw – Phyrexian Arena, Promise of Power, Ancient Craving, Night’s Whisper – but it usually comes at a pretty significant cost of life.  That has to be managed or offset. 
Moriok Replica fits the theme nicely.  Good call.
.  .  .  .  .
THE MANA BASE
My Kuon deck was built with the Drain Life mechanic in mind, so it was very heavy on mana acceleration.  The short list:
Indeed, this did the trick when fueling out giant Exsanguinates, but the deck also tended to have to play out like a combo build due to the frailty of the accelerators.  Let’s face it…no one lets Coffers stick around for long and permanents get destroyed left and right.  I found myself doing math in most cases that involved dropping Caged Sun on the same turn I needed to use it, for fear that it would just be destroyed in short order anyway.
Let’s face it…black just ain’t green.  But how much do we really need with Xiahou Dun? 
In this section, we’ll look at the options for the deck, think a little about what constraints and opportunities paint the needs the deck will have for acceleration and fixing, and define some areas we can draw on when the deck starts to take shape.
CONSIDERATIONS-
-Xiahou Dun himself
Ideally, Xiahou will always cost four mana when counting on something like Dawn of the Dead or Phyrexian Reclamation.  Sometimes, that’s just not going to be the case, and general tax will be accrued. 
Retaining ‘Drain Life’-style components
It’s hard to get completely away from running stuff like this in black.  Even if the goal isn’t a huge Corrupt, we’ve identified that the draw this deck will be running is very taxing to life totals.
-Mechanics and engines  
How smooth will this deck run, and how mana-hungry will it end up?  Let’s look at three recursion sources that get Xiahou Dun into play at least one time:
  1. Haunted Crossroads, putting Xiahou Dun on the library, then drawing an playing him. 
NET COST – 4BBBB, one draw step
  1. Phyrexian Reclamation, returning Xiahou Dun to hand and replaying him.  
NET COST – 3BBBB, two life
     
  1. Dawn Of The Dead, putting Xiahou Dun into play.
NET COST – 2BBB, one life
Clearly, this is a dumbed-down comparison, but it’s important to keep in mind how current and future costs will impact the deck.  What is the opportunity cost for the first example?  You’re missing a new card from your library during your draw step, forcing you to play from your graveyard.  If you need a board sweeper to save yourself that turn, can you afford to also recur and play Decree of Pain, or is it worth it to instead see what your regular draw would bring? 
How good is Phyrexian Reclamation when you’re at low life totals?
What doors open up from Dawn of the Dead costing 2BBB up-front, but nothing save a single life a turn from there on out?
The lesson here is that how the deck is designed to function and the options it has at its disposal will directly affect how much it costs to run, and how well it runs.  
OPTIONS-
Scalable Acceleration
-Jet Medallion
-Caged Sun
-Gauntlet of Power
-Black Market
-Nirkana Revenant
This category excites me the most, since the costs associated with making mana fall off completely once you untap with them in play and they immediately provide a benefit.  Options that grow mechanically (Black Market) and options that don’t affect opponents (Caged Sun vs. Gauntlet of Power) are preferred here, as are the mana doublers, but profile is key as well; Jet Medallion isn’t going to sent a white player scurrying off to find Austere Command as fast as Caged Sun will.
Fixed Acceleration
-Sol Ring
-Darksteel Ingot
-Magus of the Coffers
How much of a necessary evil these are depends on how much mana the deck ends up needing to make.  Something as fragile as Magus should be avoided as a critical accelerator unless the benefit offsets the risk.  (Exsanguinate, I’m talking to you.)  Typically, I want to run Sol Ring and Ingot and look elsewhere.
Lands
Cabal Coffers
-Crypt of Agadeem
-Vesuva
Similar to the last section, the goal is to make use of these kinds of lands as sparingly as possible to prevent a blowout if someone decides to get crazy with Dust Bowl.  Crypt of Agadeem is very situational, and it remains to be seen if it will be worth the include.  Coffers is likely an auto-include, and most of the rest fall somewhere in the middle.  
Increasing Land Counts
-Solemn Simulacrum
We’re basically trying to mimic green ramp here.  Options like this are valued very much dependant on the opportunity cost.
Liliana OTDR is an interesting case, in that she fits this category as well as the first category.  I’m typically wary of running Planeswalkers in general, but if I can get my hands on a copy here, I think it’ll be too compelling to not try.
WRAPPING UP
I think that’s a good start on developing an idea of how Xiahou Dun will make mana.  Once things start to be fleshed out as far as function and strategy, we’ll have a better idea on both what kinds of mana enablers fit the shell, as well as how many.  We’ll also be able to better define the land count once we know what portion of things are dedicated to finding lands, and what utility we’ll need otherwise from our lands.
Did I miss anything?  This was painted with fairly broad strokes, so I’m sure there are low-hanging options not listed.  What are they? 
Am I on target with my assessments?
Let me know in the “Comments”.  Next up, we’re tackling core functionality – what is the primary game plan of the deck, what engines fit the bill, and what value can we build in overall?
Have a great weekend, folks-
àDJ