I'm aware of the PrimeSense camera powering the Kinect. Are more advanced sensor types available now in the < $500 range? For example, has there been any sort of game-changer in structured light techniques? Do decent flash lidar cameras exist now?
I guess that the approach in structured cameras is pretty much the same.
However, the world is trying to minify this kind of sensors. In particular
Some people speculate that the reason for kinect to be so big is the array of microphones that allows to localize source of noise.
I haven't heard of anything else, though if I find new info I will expand my answer.