You want an on-screen touchpad? In principle the button/movement part is possible with xdotool. One would need another program to create the interface that grabs the mouse actions. Zenity could do the mouse buttons but I have no idea if it could do something like a touchpad. It would have to be some transparent form covering the whole screen but then there is the problem how to tell the difference between a simple mouse movement and a a marking action. And one couldn't simply click on any elements on the desktop unless the mouse pointer is exactly above it. So the usual touch-screen feeling would get lost. I don't think that it's feasible with a reasonable effort and to a reasonable level of usability. What I think could be useful is some kind of d-pad. This could either be on-screen or on the hardware keyboard (switching between d-pad and normal keyboard via some modifier - much like the num-pad switching on laptop keyboards without dedicated num-pads). I think the latter option would be better. Could we somehow use the camera button for that switch? I know there is a program in the Maemo repository that allows to customize the action that is performed when the camera button is pressed. But I haven't tried it so far.