I have considered what Taipan was saying in regards to just getting a small 16:9 non-touchscreen to save some $$. Then to cover control buy a cheap usb gamepad and mount it behind the front of the case instead of using the remote.
Taipan: The clone mode of the nvidia driver was my first thought as well, but therefore the touchscreen must be able to display the same resolution as the other display, i.e. 1280x720 in my case. I think the one that comes with a silverstone lc18 can do that resolution but I'm not sure if the (cheaper) Dign X15e is capable of this. But anway I don't think that clone mode is a solution to your problem as MP doesn't use overlay mode any more as far as I know. Please correct me if I'm wrong, but at least TV doesn't use overlay but VMR9 (It is transmitted via VNC which should only be the case if it's not overlay).
Does anyone know any cases with touchscreens other than LC18 and X15e? Or does anyone use one of them? Just want to know what resolutions they definately support... The webpages only tell the native resolution.