Not that the Thingiverse lacks skull models, but here's my contribution: I took the skull from http://www.thingiverse.com/thing:12857 and the mandible and teeth from http://www.thingiverse.com/thing:27944 and cleaned them in blender and meshlab, then combined them. No non-manifold faces, no screwy geometry.

I haven't printed it yet, but it should be doable. Just throw it in SF, center it on the build platform how you want it, and hit go. It's scaled to be as large as possible for a TOM, so you might want to scale it down to save plastic.