The iPad2 does support full mirroring (not the iPad1) - you would need either a VGA connector (for a projector or computer monitor) or a HDMI connector (for most modern TV sets).
Another option that might be helpful, although not in the exact way you're describing: I use a desktop control program (Splashtop) that allows me to control the computer from the iPad. In the classroom, I've connected my computer to a projector and then from the front of the room controlled it with the iPad - the students see on the big screen what I'm doing on the computer, but I'm doing all the work via iPad. The downside of this is that many of the computer apps don't respond as well to the touchscreen infterface. It might, however, allow work on the computer to be done via iPad ... the upcoming Lion OS for Macs might be very helpful for this kind of work.
There have been discussions on this forum about sterilizing and cleaning iPads - I can't recall the specifics, but I believe the feeling was that medical-level cleaners would damage the iPad. A heavy-duty case (such as the Otterbox) plus a clear screen protector (which might be more tolerant of stronger cleaners) might be a good solution for those issues.
I have been using Hippo Remote app on mac and iphone to turn device into a controller (mouse and remote) for my MacBook Pro.
I have a friend who has MND and uses an iPad as a communication device. I am not sure what the app is but I am sure it will be easy to find on the app store under Medical category. I think the app is approx £120.00 but it is a godsend from what I can gather.
Sorry to be vague but hope this helps.