Some of us are probably aware of Johnny Lee's hardhacked Wiimote, providing head track 3d on a budget. For anyone that's not familiar with it, the tech works by taking advantage of human's other (besides stereo vision) great 3d sensing technique, parallax. Parallax is best explained by imagining the scene out of a speeding car's passenger window. Objects far away from you appear to move slowly, while objects close to the roadway zip by at 60 mph. These speed differences are extrapolated into three dimensional information by the brain. Head track 3d works by updating the parallax of objects in a rendered scene based on the motion of the viewer. This creates a very convincing 3d effect. This idea has already been used in some DSi games. The downside is that if the viewer stops moving, the effect disappears, making it impractical for most gaming genres.
I'll bet you can see were I'm going with this. Kinect gamers are moving around a lot, and the tech has a built in ability to track the viewer's head. So the question is, why isn't every one of these games supporting at least an option for head track 3d? We know the processor overhead isn't huge, because we've seen it running on the DSi. Of course, it wouldn't work for two players, and there would be a some subset of players who found the effect nauseating. But, we are talking about glasses-free 3d on our existing televisions, right on down to NTSC CRTs! That sounds huge to me. Frankly, I'm astonished the release dev's didn't pounce on the idea.
But wait, there's more! I know that the 360 doesn't currently support true stereoscopic 3d, but it's merely yet another HDMI upgrade away from doing so. For the sake of argument, let's imagine that Microsoft decides to support the HDMI 1.4 spec somewhere out in the future, either at the next hardware revision of the 360 or at the next generation of the console. A big problem with stereoscopic tech has been that when you move your head, the illusion falls apart because objects don't parallax as expected. Now imagine a combination of head tracking and stereoscopic 3d. The effect that this would create would be very similar to a hologram, in that, as long as an in-game object was between you and your tv, you could walk partway around it to examine hidden details. That is not only huge, that's epic fricken huge.
Since I'm dreaming here, let's also imagine that Microsoft breaks down and releases a 1:1 motion sensing wand with this hypothetical hardware update, quite similar to the Move's wand (and yet branded quite distinctively I'm sure). Then, we'd be at a point where we could reach out our wands, pick up our holographic virtual possessions, rotate them in the sparkling virtual light, with the biggest grins we've had on our faces since Mario 64.
Hacker allready has basic headtracking up and running.