soul eater1 lets you bestow a negative level or 2 with a touch
so the name of the game here is extra attacks = more negative levels, snap kick, natural weapons, monks belt(debatable for non-monks) etc...
9 levels and your victims raise as wights: no HD limit on this
(steep prerequisites though: non-humanoid(monstrous humanoid ok; so pretty much warforged), a natural weapon, some BAB, 2 feats, evil)
dread necromancer1 gives you charnel touch(debatable whether this stacks w/ unarmed attacks, last I looked)
thrallherd1: lots of minions that you can have attack with their fists too/ or fill other roles
(EDIT: IIRC kalashtar can get this easily)
cleric1 can get you two domain powers, and/or 2 feats (hunger gets you a bite attack for example)
(EDIT:war domain grants weapon focus for your deities favored weapon, and some draconomicon deities have bite as a favored weapon(meets a soul eater prereq))
EDIT EDIT: holy crap!, idk if this works or not.. but only requires 4 levels
Kalashtar: Divine Minion1(type changes to outsider WS is just gravy), cleric1(hunger for bite attack, war for weapon focus: bite), sword sage or whatever you wantX, at some point take thrallherd1, sould eater1, whateverX
(flavor wise contradictory and deity choices get a little hairy, but if you're allowed to re-flavor.... could be interesting)