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.