Make a white box, set up a video camera on a tripod, and then pick the best hand model among you.
A common problem found when screen capturing app demos is nothing to do with the technology or framerate issues, but it's the fact the audience cant tell what's happeningthey can't see what buttons are being pushed, any accelerometer motions, any gestures. You can add these after, visually, but it gets confusing then. If you haven't considered this already, it's worth thinking about now, because i've seen lot of devs go to the effort of jail breaking, screen capping, etc. only to find it's too confusing to the viewers and they end up shooting it on camera.