My daughter has cerebral palsy and very limited speech capabilities for use in general communication, much less in classroom settings. She has wonderful computer skills (I think the kid is smarter than I am, but at least for a while I will still be bigger than she is!), and she is very capable of using the keyboard, but it is very slow and it just isn't portable. We have, on a number of occasions, considered (and rejected) the possibility of a communications device that would allow her to generate her own responses. In order to have it available and positioned for her to use, she would have to have a laptray on her wheelchair. That means she can't get under a standard desk/table and immediately feels physically isolated from those around her. This summer, she discovered cells phones, with text messaging. Someone showed her a way to tie her text messaging into the instant messaging function on her computer, so she can send text messages to other cell phones and/or she can have IM conversations.
The cell phone eliminates ALL the significant problems of a traditional communication device -- or a keyboard, for that matter! It is small enough that she doesn't have to shift her vision -- no visual tracking problems. It fits in one hand (and is light weight) while her GOOD hand does the work -- no significant coordination of movement to worry about. It requires the minimum amount of effort/movement to operate (just the single motion of that thumb, up and down!) and, best of all, it is MEANT to be portable and available. And it isn't adaptive equipment at all -- it is every teenagers standard fare! She can (and does) text message faster than I can.
We have already found one classroom use for the cell phone. She had to give an impromptu speech in a class last week on a subject of the teacher's choosing. She chose her topic out of a fishbowl, then went to the back of the room and sent her speech to the teacher's computer, creating it as a series of IM messages. When she had finished the speech, a classmate read it aloud off the teacher's screen. I think it offers some real possibiities for communication in hybrid classes, but am interested to hear any ideas others may have for alternative ways to put the technology to work.
By the way -- it DOES have a cost involved. I had to switch my cell phone coverage to "unlimited text messaging" at $15 US/month. It's a good thing I did, as the first month she sent/received 2938 messages!!!
In the past, I've worked in a Special School, and I know just what you mean about the difficulty of getting a child with a VOCA up close to a table, when the VOCA's fixed to the wheelchair. Most of the children that I've worked with in the past, just didn't have the fine motor skills that your daughter clearly has - there's no way they'd have been able to use a phone!
However, to get the point that I was going to make - the thing I saw in the summer was a communication aid (I think they were aiming at children on the autistic spectrum to start with) for a PDA. Clearly a PDA is well outside the $200 price range (unless they're a lot cheaper outside the UK!), but the software is currently free - though in Spanish; and they've got a prototype. The company is Axistive.
I've not seen it in action, but it looks as if it could have potential. I'm also not sure what the price will be once it's out of the prototype stages.
Have you considered a Blackberry? Itis basically a text only device that will interface with IM and email for computers. There are a variety of these out there. I know a many of my Deaf friends use this as a communication device with friends and family. The whole things is small enough to fit into one hand and basically has a regular keyboard on it. If she is good with one handed typing this would work for her and it becomes easier since she doesn't have to remember how many times she punches a button to get the correct letter. (my daughter has that down to a fine science) This may be an option to look into.