Hi,
I have a few thoughts on the P800 that I thought I should share with you so that maybe you could take it further.
Playing games
Is not easy with the lack of control.
How about cutting your flip down keyboard down to the last three buttons, or a 3rd party making a new one that had a thumb pad on which worked on pressure. this would make the screen slightly smaller but a good trade off for better control.
Or a clip on unit which replaces the clip on keyboard and cover which has a thumb pad and buttons on.
Theses would either attached to the connector underneath or have some kind of mech which put pressure on the bottom of the screen.
Or if you dont use your flip keyboard the a cover which has a button on which uses the button which lets the OS know if the flip is open or closed ( not sure if this could be reprogrammed )
One last control method a bit far fetched but maybe possible depending on the cpu usage of what I am about to suggest. The camera if taking in information should be able to see which way the phone is moving, so small movements to the left and right could be detected by the camera and transfered into left and right movements of a game!! similar to the way an optical mouse works.
Music
Years ago I had a walkman that was controlled by one button similar to the one button on th head phones. It worked in a kind of morse code, one short press=stop, long press=play, two short press=rewind etc.
this would be good for varios remote control of your device, maybe!
One last thing is that I haven't seen many people talking about backgrounds etc, anyway I though it would be fun to have backgrounds with areas difined where the icons appear. I have this one below which I knocked up realy quick and guessed on the position of the areas so they are a bit off, anyway maybe some of you photoshop experts can do something a lot better.
thanks