Hi Molly: I think this is an excellent idea. A concept like this has come up a number of times in discussions by our community of "Longevity Explorers" (older adults exploring the intersection of technology and aging). Quite a few of our explorers like the basic idea, which is good news. :)
I have the impression that the technology may not be quite there yet, but then again maybe it just needs to be pulled together. If you decide to proceed with this, we may be able to help.
I think this is a great idea. In fact our community of Longevity Explorers (older adults who are interested in this sort of stuff) recently had a series of discussions about gait and peripheral neuropathy, and about how someone really needed to invent something just like this. :)
I and some colleagues have an interest in getting involved in some prototyping of ideas like this. We are based in the SF Bay Area and have deep roots into both the tech industry and the aging services industry.