It will be interesting to see what direction they go with their handheld development with the release of the WiiU. The controller for that could be considered a handheld.

I once saw a blind man being led by a dog. It was in a large sports stadium which had diagonal structural supports along a corridor. The dog was leading the man under one such support where I witnessed him walk into the concrete at head level. I would imagine this could be a great help in such a scenario.