Well, if you can get your DM to waive the Turn Undead Prereq, the Hunter of the Dead PrC in the Complete Warrior is pretty much what you're looking for. Maybe replace turn undead with favored enemy: Undead? Anyway, here's a summary of the class abilities:
d8 Hit Die
Full BAB
Good Fort, Bad Reflex/Will
Detect Undead at will, Smite Undead (similar to paladin smite evil, only undead instead), apply wis modifier twice to will saves vs undead, undead killed by you are dead forever, cannot be energy drained by undead, etc
Some divine spellcasting in there, but if you can work out the details with your DM, I think it'll work nicely.
Because turning undead is a prereq, they gain extra turning attempts and a move that uses turning attempts to deal damage. But they could easily be replaced with Improved Favored enemy and an ability that lets you crit undead. Just some thoughts.
Also, though I don't have it on hand, the 3.0 PHB makes a reference to an alternate fighter that uses the rogue's weapon/armor proficiency, saves and skills, (but keeps the BAB and Hit die,) and has the sneak attack only apply to undead creatures. At least, I think it does...
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