All good ideas. But four buttons + two shoulder buttons has obvious "backward compatibility" advantages, as well as being just a sensible layout.

Four buttons could be used as Home/Menu/Back/Forward in the Nokia applications, and then become ABXY in games. Shoulder buttons could double as back/forward, or be treated as control-shift.

Now, I understand that the tilt sensors in the likes of the Sixaxis controller have actually become cheap and tiny. If so, it would be amazing to contemplate having this in a N900, and being among other things able to treat it as a joystick. We could have almost any type of game with that set of controls.

I'm convinced if Nokia included all of those things (4 buttons, shoulder buttons, tilt controller, 3D accelerator) that they would sell at least twice as many N900s.