I think the magic of the hardware is in the infra-red grid scattering as seen in the night-shot video in the link and (I believe, but correct me if I'm wrong) hardware level processing of that returned data from the camera... I'm sure similar setups could be engineered, but the problem is environmental control... In order to make something distributable, you'd have to find a supplier of the same light scattering system as the software author, the same webcam(s) and the placement of everything would need to be precise... The kinect is an all in one solution to that, available nearly anywhere, cost effective, and very predictable... My girlfriend is going in to Occupational Therapy and recently did a study on assistive technologies, the constant theme for all those devices was insane price points. If you follow the link in the article and watch the video of yankeyan and his object recognition technology mash up using kinect as the hardware interface, it opens a world of possibilities for open-source and very affordable assistive technologies using the kinect. Just like the NY Times article about the iPad helping those with disabilities, I think the kinect could be another low cost assistive technology platform in it's infancy.

I can think of a lot of great uses for this technology.... I hope these hardware hackers keep it up

And then three dozen /. users teamed up against the two dozen (EDIT: two dozen and one) ./ users and said "Keep your dots and slashes! We like our slashes and dots!" and sent them home crying to their mommies....