We have Cowboys & Aliens, and Zombies vs Robots, so it was inevitable that someone was going to take this to even more extreme levels. Enter Jonah Hill (Superbad) who's first crack at directing may be on a script called The Kitchen Sink, which "sees teenagers of the zombies and vampire variety who must all band together and suppress their urge to kill each other long enough to repel an alien invasion".
I can see how something like this could be really funny if done right, but of course, this is still at the discussion stage. Zombies are a hot property right now and while there are zombie stories being bought up by studios left and right, I wonder how many of these projects will actually see the light of day.