This has existed for a while in the military training space, although I'm sure the economics are only starting to make sense for consumers now (it might still b

This has existed for a while in the military training space, although I'm sure the economics are only starting to make sense for consumers now (it might still be too early, no idea). I worked in a slightly related field over five years ago, and saw several such systems on display at conferences (and got to play with them, etc--very cool tech). Here's the first Youtube video I could find[0] demonstrating the concept. 0. http://www.youtube.com/watch?v=ja6oy3I1rdw http://www.youtube.com/watch?v=ja6oy3I1rdw