I'm not visually impaired, and I can see it being useful to me as well. This project would also enable blind users to be a part of the maemo community. An n900 with open source software for accessibility is a lot cheaper than any similar devices, so there's a lot of value in that alone.
Part of this project would be to create a launcher for visually impaired users to open accessible applications. In particular, I would like to make the phone accessible if I have time, so blind users can carry an n900 in place of their current phone as well. Based on discussions on irc, this would probably be something more simplistic than making hildon-desktop accessible for the purposes of SoC