I like the idea of a touch screen that you don't touch. Just a few centimeters(variable) off would be fine - they do exist but I've never used one. I think what's required is a way to slightly flex one finger to activate cursor movement, then pinky/thumb twitch to button press. Maybe wear two magnetic silicone nail bands? Current air-touch technologies seem complex and power-hungry, I don't know.

Would be tiresome though to hold hand out all day - but good for mobile and handwriting/drawing. Need zero latency.

Furthermore, the mousepad could become the magnetic sensor and not the screen in order to rest the palm. The nail bands then become the equivalent of the mouse so it's a hall effect mouse. But could the pad detect finger twitch for the buttons, though?