Mono-White Sly

Very true, I run 2 Phyrexian Obliterator in my mono black vampire deck.  The question arises: Why would you not run the Obliterator in a mono black deck???  I did run 2 Abyssal Persecutor as well but I found them less effective with the theme.

It is a good point to make. I use Grand Architects in variants of my Merfolk deck along with Thada Adel, Acquisitor and since I can, Myr Superion.

I completely agree with blackjester. A themed deck is fun to play, but most of the time are not any good. When building a homebrew, think of all the top decks to beat: solarflare, wolf run, tempered steel, mono red, GW humans.... Etc. If your deck triumphs against those, your good to go!