Matt,
Any user "training" needed on the Pronto in my oppinion is far and away outweighed by it's graphic nature. You ask about resizing buttons? How about importing your own buttons? Like perhaps an icon for ABC, CBS, NBC, A&E, DSC, DIS etc etc etc. It would seem to me that this feature (any size you want up to the size of the screen) and the fact that if you need more, then just croll one menu down etc etc etc.
The ProntoEdit PC software provides this power and is expected to become available in release in about 2 weeks to coincide with the CES show.
I've been playing with beta version and all I can say is it's great! The release version is expected to be even better.