I'd be surprised if Sam Black didn't have a similar deck written down somewhere.
Let's start with the obvious -- Disciple of Deceit, discarding a Gravecrawler or Bloodghast, searching for another copy. That's some pretty good value and, together with Smallpox, can put your opponent under the gun relatively quickly. If you can keep your Disciple of Deceit alive and inspired, you might be able to Smallpox four turns in a row!
On the second level, we have another Disciple of Deceit combo, this time involving Lingering Souls. Again, you can discard a copy to find another copy, but you can also search for a Sword to give you protection from whatever color is ailing you. A singleton Liliana of the Veil to search for might have a place in this deck. It also works pretty well with the rest of a deck that's already combo-ing with Disciple of Deceit.
With all the toolbox capabilities available, I was pretty impressed with how tight Pr0xies kept the maindeck, but the sideboard is another story. With ten different one-ofs, you've certainly got a lot of options. It's pretty clear that Disciple of Deceit allows you to go pretty deep and play a lot of pretty crazy cards and interactions, and this decklist is probably only scratching the surface.
- 4 Tidehollow Sculler
- 4 Bloodghast
- 4 Disciple of Deceit
- 4 Gravecrawler
- 2 Snapcaster Mage
- 2 Xathrid Necromancer