We have been using the Click-n-Type On-Screen Keyboard with her and an open Word document. I have used the Click-n-type because it is free, has word prediction and is size-adjustable. But for this particular student, we have a need to adjust her keyboard more and today I found Comfort Software's On-Screen Keyboard Package. You can get a basic set for $9.95 or the fully customizable set with all the bells and whistles for $19.95. You can download it for free and use for 30 days to try it out.
I found over 40 different styles of keyboards with word prediction, opacity settings, and thematic backgrounds such as jelly beans, watercolor art, bubbles, dew on a leaf, etc.
There are multimedia keyboards, ergonomic keyboards, split ones, vertical ones, circle key keyboards, etc. There are fully assignable hot keys and you can design and save your own customized keyboards. All this for $19.95.
I have experimented with a lot of on screen keyboards and for the price, this one is terrific. I would love to try it out on a Dynavox V Max with the Touch screen PC part turned on!
I would highly recommend checking Comfort Software out...
All the best to you!