On a similar note, check out Northpaw, a project to help people develop a sense of north - http://sensebridge.net/projects/northpaw/. This exact same method might actually be an easier way to get wearable navigational aids, as it will work with all shoes.

What I found interesting was that the insoles featured had a surprisingly similar height profile to my medical orthotic insoles for pes cavovarus (high arches, inward-turned heels)[1]. I'm all for tech that fits disabilities by default! (although this is probably an accidental by-product of the required space for the tech)