A google search actually yielded some good info on this --

[Link: carelusa.com]

lists several products that at least at first glance look like they could be what you are looking for. I take it this is like a prototyping project because it is far from the usual project and everything needs to be custom. These guys might supply a sample, especially if you offer to write up how to apply their product for handicapped use. That could make them look good and even get a publishing credit for you!