I'm thinking something along the lines off;
Incarnate 5
Ur Priest 2
And follow that by the dual progression Divine/Meldshaper and eventually dip 1 into Necrocarnate.
thoughts?
EDIT: Venn, how do you feel about me starting with a corpse to animate?
And don't worry everyone, I'm buying an Enveloping Pit.
So what are you planning to do with this build? I'm going to warn you, playing an evil character in a group of mostly good and neutral characters will most likely put you at odds sometimes. While Eberron is largely a morally grey world, there are pockets of extreme alignments, and if you go around exploiting corpses for evil purposes you might get a group of Silver Flame zealots on your ass. To that extent, Karma plays a big part in the game, though it's not a moral thing so much as an overall balancer.
Also, yikes, I'm pretty sure I'm not allowing you to have a 6-headed undead cryohydra. 18d6 breath weapon damage?
I'll stick you guys in the Frostfell so it can't do any damage.
Seriously though, I'm trying to keep things from going over what I can handle. Though I'm allowing all sorts of houserules and other content, I'm still rather a newbie DM. I can deal with the Druid having a fleshraker animal companion, and some of the other tricks going on, but the more minions and cohorts there are the more difficult it is to keep track of things. I'm really not happy with allowing minions with 6+ attacks per round, Fast Healing 16, and a boatload of immunities.
You guys should be fighting things like this, not having them give you pony-rides into battle.