The folks over at Beasts of War have submitted some Spearhead lists for xenos, and the 'nid list has NINE carnifexes in it. The carnifex is my all time favorite model, and it actually got me back into the game.
I think I may wait a bit, though, until I can see if Spearhead gains some traction. Still, I should have picked up a few on Ebay when everyone was dumping them when the new codex came out. Ugh.