A touch screen is considered a pointing device, and that is how XP sees it. Drivers for the touch screen should come with whatever monitor you buy.
RE: the resolution being weak. The resolution you use will depend on the monitor you buy. The touch screen does not change or limit the resolution you can use. You can buy monitors with touch screens already attached, or add 1 to an existing monitor, with slight modifications. You can also build your own setup using the required components, if you are considering a custom in dash install.