That would be cool if they would allow you to jerry-rig one yourself, lol. It needs to sit at the opposite side of the room, across from your TV. The kinect reads what's going on screen as well as uses the 3d data around the tv and creates the effects( my favorite being the grenades "warping" the cabinets around the TV. It can also be directly plugged into your game machine to extend the graphics outside the TV(which would take more rendering power). It's connected to the projector.
You can get SD projectors dirt cheap, and I don't see why you would need more than that.
I also like how it can show stuff on the wall "behind" the entertainment center by cutting out the foreground cabinet. Also how the snow would accumulate on the shelves. Awesome stuff.
Here is a longer vid