Not sure if anyone has made official undead unless ashlings count. To conjecture, we have those soul bits that could be caught before they reach the wraithstone. You could stick them in a new body and raise it as a zaumbeh. Of course, this stuff would give you a guaranteed disapproval from our friend, the icy-death-genocide man.
Edit: Legion02 gave a better answer.
Edit: Legion02 gave a better answer.