Not the best place for this topic. But since 98/Me/XP/Vista can handle multiple mouse/keyboard combos (the wonder of USB)... I don't see why two more input device (Touch Screens) would cause a problem.
The best place to get an answer to that might be the maker(s) of the Touch Screen Monitors.
As far as this relating to UTV... Has anyone tried to get a USB Mouse to "navigate" the UTV Interface? I know some have used USB Keyboards for basic functions. If anyone has been successful with using a USB mouse... I could see the potential for a "Touch Screen" Monitor with A/V input and a USB "Legacy Support" interface have a cool chance of working.