I also would stick with the touch screen for academics for now, but wanted to give you another option that might help your student learn to use a mouse in the future. The program by Softtouch 'Teaching Access Ability' (
http://www.softtouch.com/teachingaccessability.aspx ) is really great for helping a student make the connection between the mouse and the screen movement. It's very sequential, teaches the student to move a large picture (vs. a small cursor) left then right, then to computer vs. trash can (one plays an animation, the other does nothing), then up and down, etc. It's very simple but engaging. If you go to the website above, click on 'more images' under the picture, the second page shows you the sequence. I think it's $130.00. I used it with a student who has autism and a very low IQ, with a BigTrac Roller Ball. It took a couple months (at 1/2 hr. 1x week), but when she finally 'got it', the jump to using a regular mouse was really fast.