Thanks for the comments! I am familiar with touchpads and have used them in the past, and they are very useful.
Maybe I should ask the question a different way: I have a graphics card which supports multiple monitors. If I have three monitors, is it possible for one of the three to be have touch capabilities? If so, could I use that screen to start and otherwise control programs that would appear on the standard screens?
To my mind, it would simply be a touchpad with a screen (like some of the touch-capable handheld video games) controlling larger standard monitors.
I can think of all sorts of reasons why this wouldn't work very well, because Windows 8 is designed for a single-screen tablet, but it would be very cool if I'm wrong.