Firstly I'd like to say thanks for all the help. To clarify things a bit, my character isnt going to be an undead.
For a little bit of back story the party just finished escaping from/clearing out an undead infested barrow which they entered hoping to find the source of a rash of recent undead attacks in the area. Instead they found an alter to an unspecified evil deity that was missing a prominent relic. With his dying breath the vampire (i think) that was in charge of the barrow told the party that it was too late of the surface dweller that stole the relic because he, the vampire, had "released hell on earth" to retrieve it.
My character is making an entrance as the "surface dweller" who is currently in possession of the relic and being hunted by the undead.
Dredan: Thanks, although I dont think a whole new campaign setting is what the DM is really looking for since the story is heavily involved with its Eberron settings.
Stream: I dont have the book of vile darkness, but I'm pretty sure that one of my friends probably does so I'll take a look at that one
Shin: I actually didnt even think of using regular PC classes to enhance the undead, using Ghostfaced Killer might be the way to go if i cant find any straight up monster that I like