now here is an interesting concept that is realistic. first i'll link a cnn report (note the designer states you can't just tie a wheelchair down), then i'll link a video. this concept fascinates me and i will try to contact the engineers behind this design for more details.

http://edition.cnn.com/video/data/2....ravel.cnn.html

http://www.youtube.com/watch?v=3Q1LwAvdTXY

what do you think?