Well, when I'm booted into Windows, I can't model edit because every time I attempt to launch the game it crashes. I found that when I'm booted into Mac OS X the model edits still work fine (I have human to undead), all it does is show an error message that I can close but the game still plays fine.
Maybe if there was a way to get rid of this message in the Windows version of the game, race to race model editing would be possible to do.