Hmm bizarre, can't say I've seen anything like that. Anything special in the scene? Any spew in the editor log after the crash?
Nope, Unity simply freezes and I have to force close it.
The scene contains an interface made with 2D Toolkit cameras and anchors (but no tk2dUI), my pooling system, tweens of various kinds, and regular 3D objects, and it's the same scene I work on since months (since it randomly generates content).
Again, it's quite bizarre indeed, and something might've happened unrelated to 2D Toolkit (I mean, that was the only asset/big-chunk-of-code I updated before this started happening almost immediately after, but still, Unity sometimes is strange). And Unity freezes a lot less since updating from 2.1 to 2.2.