@Quantumphysics:

http://www.freedomscientific.com/products/fs/focus-product-page.asp

Dynamic Braille displays like that are used all over. Of course no one would mind them being cheaper, but they are there.

These sorts of systems are already far beyond the research level. I sat in a conference today and heard all about how companies like Rest Assured (http://www.restassuredsystem.com/index2.htm), Sound Response (http://cow.waisman.wisc.edu/soundresponse.html), and Imagine! Colorado (http://www.imaginecolorado.org/) have been running systems like this for years. Some of them serve hundreds of clients, from the elderly to people with disabilities, and have saved other programs millions of dollars on live-in caregivers.

Wow, you guys have some pretty impressive solutions already. Thanks for adding to my assistive technology/computer access toolbox, which has been growing steadily since I recently started working as an AT engineer (in Denver).

I was also going to suggest Joy2Key. Also, I work with someone who has muscular dystrophy, and plays WoW with an XBox 360 controller. Because they are USB-based, they can be used with a PC easily, by downloading a simple driver.

Joy2Key:
http://www.oneswitch.org.uk/2/I/JoyToKey/JoyToKey.htm