Is there anyway to "overhaul" the keyboard software? Not just to modify it to make it more user friendly, but to be able to extend the functionality quite further than that (the existing solution seems somewhat limited/difficult to modify for a beginning user).

Things that would work excellently for a new keyboard system:
- (as mentioned previously): profiles, which could be saved and activated/switched to with a taskbar app
- drag and drop keyboard rearranging support
(just drag keys to new locations/remove keys you don't want/add keys you do)
- extensive themes, not just for aesthetic purposes, but also for user personalization
(eg. a user is used to the android/ipod/any other phone onscreen keyboard could get a "theme" that just reorders the keys and changes the look to match the keyboard they are used to). This would help the user feel at "home" with the device much quicker than having to readjust to how to type on the n900.