Don't know how far this takes you to what you are looking for, but you could give The Colour Is .. a try, available for download at http://www.fxc.btinternet.co.uk on the Assistive Software page, near the bottom of the page

Works in all versions of Vista too, but rumour has it that it can upset 64 bit versions.  I have it sat on the desktop of all my machines.

I've got one of the Virtually Indestructible ones in my kit.  I suggest them to users for many reasons.  Light weight and easy to pop in a laptop bag for anyone with RSI, good in preventing people with behavioural problems from bashing the keyboard, also good in situations where the user may spread saliva on the desk, and some people simply like them - takes some people back to the old Sinclair Spectrum days