I happened across this video today and I thought somebody else might like to see it.  I've never seen one of these in real life but I think it's a neat idea and would make a cool project for someone.  I wasn't sure if this was the best location to post this so feel free to move this thread.  Also,  I haven't seen this posted before but if it was I apologize in advance for the repeat.  Anyway, here's the link to the video:
http://www.youtube.com/watch?v=crwcq-c7peU
Disclaimer: I have no affiliation with this company, just thought it was a cool video.