There are already homebrew demos of a "lightsaber" using Kinect on a PC.
It has the characteristic Kinect lag that many have already accepted as being normal, but the coder was using a mundane prop in his hands that looked and moved like a lightsaber on screen.
The problem is, you need the prop, which is not to say that they can't ship a piece of plastic with a Star Wars game or let you "scan" and use your own. It would be a better option than any empty handed pantomime sword swinging. Try doing a phantom base ball bat swing with nothing in your hands and you'll agree.
Regardless, I have no hopes for the Kinect Star Wars rail game that was demoed at E3. It seriously looked like an XBLA game, and not a good one at that.
And yes, I think it's only a matter of time before one is made for Move with controls that should be fairly difficult to screw up.
