Tablet for augmentative and alternative communication (AAC) app?

[Guest English Haze]

I'm developing an Android tablet app. aimed at providing an AAC device for people with sight and speech disabilities.

There are plenty of AAC apps around that have nice colourful symbols and fancy graphic designs but all of that is useless if your user can't see too well so my app is designed to work on touch and sound alone with no fancy graphics.

I have a prototype built that works in the emulator but I'm now looking for a suitable "cheap" tablet to test it out in the real world.

It must have at least Honeycomb OS, ideally 8-10" display (I think 7" may be too small), support haptic feedback via a vibration motor or similar, have a decent capacitive touch screen (multi-touch not required) and obviously have audio for speech synthesis.

Suggestions?

I'm also keen to know of ways to "lock" an app on the screen to prevent inadvertently hitting the back, menu and home buttons that might cause a problem for a blind person. They should be able to feel around the display and only the buttons in my app should respond to touch by vibration and sound. Can the home, menu and back buttons be disabled in code? I realise I'd need some mechanism to quit the app. to return to the home screen.

Thanks for any help or suggestions.

[Guest English Haze]

No one has any ideas or suggestions?