This is a touch screen keyboard rig I currently use at some of my gigs. The touch screen is a Music Pad Pro which several of us in this forum use. I am using it both for music display and backing MP3 file playback. By good fortune it happens to lock onto the metal music stand of the Kawai ES4 piano so it's rock-solid and I can use it easily. The audio output of the MPP routes through the internal speaker system of the piano. I had hoped that one day a manufacturer would get the idea of making a truly large screen touch display was big enough for displaying full-page music in this fashion but this is probably the only way to get what I wanted anytime soon.

Functionally the touch pad works fine... it's the OS that could stand refinement and be a little easier to use on stage, but it works. As a bonus it lights me up a little at night when I play.