Ok, scracth that last thing. I'd still be willing to help model the gibs, and there's no problem with using the "spawn-gibs-at-death" method (what kadaverjack said).
Here's some ideas for gibs:
Robotic: hydraulic piston, metal shard, some kind of giant circuit board
Mutant: Same gibs, but with splotches and growths on them
Alien: An egg sack organ thing (lumpy green bag), a segmented eye, a squeedly spooch (someone decide what it looks like, it's from Invader Zim)
Humans (add?): A ragdoll intestine that unrolls (very processor intensive, not exactly a great addon) an occasional leg-bone.
Sound possible? It doesn't seem to hard even to make a ragdoll intestine (but only after the characters get ragdoll death when not gibbed)