Then how about that sort of calibration? imagine a calibration screen for dosbox for any game by key shortcut, it displays a small slide at the top and left screen border. then the software emulates first a click on [1,1] then one at exact center (or right down, which is what? [799,479]?), rinse and repeat. From the way that mouse cursor is displaced from it's intent direction one could then "scale" the mouse movement with the two sliders for vertical and horizontal movement. Once the right calibration is found for the game, just have the software make sure the mouse cursor moves from [1,1] to it's actual position in each game cycle, so the game cant screw it up.... Hmm, I think I mixed two ways to do it, there. Or zero, depending on software capabilities (how deep you can edit dosbox for this device, how much you can change when the game actually runs, etc).

I know it's not as easy as it sounds, but it's definitely possible with a hack. It works for PC,too, doesnt it? The way I get it, the PC doesnt have this issue since it's mouse always has a cursor position and cant "jump" that much, but you could do the same for the n900, the actually stylus tap only giving a direction the mouse cursor should by software move to, not directly click at, speed up clock time/skip so it looks smooth then find a way to slow the actual game itself down so only the mouse movement is working.

Or a simpler idea: just have the mouse cursor move by key press. I remember that's the way I played Zack McKracken back then, and I didn't mind much. You'd probably have to decide for certain games differently which buttons to use, but if you can access the proximity sensor during dosbox runtime, just have proximity_sensor_pressed make the arrow keys move the mouse not execute arrow_up etc. How about that? Would that be easier to do?