There are single point touch monitors, ten point and twenty point.

http://www.expertreviews.co.uk/displays/279049/3m-demos-20-point-multitouch-monitor

For the most part, you should be looking for a 10 point touch as you likely have 10 fingers and probably aren't planning to use your toes. You could still have two users recording fader automation each with using some of the available 10 points.

One point touch would kinda miss the good stuff in Sonar. Most 10 point touch monitors for 20 inches and up start around $300 and go up. The cheaper monitors seem to have trouble around the edges of the screen, which may not bother you.

I haven't seen it done, but according to Microsoft you can have more than 1 touch monitor with Windows 8.