I know the trackpad on my MacBook Pro lets you use multiple fingers on it, and a tech-savvy friend of mine said it would be possible to use it to control two pointers without much problem, except in the case of the trackpad it might have trouble telling which is which, which wouldn't be an issue with two physical mice. So I'm not sure if it's possible in windows, but it should be possible with the right software for at least mac (prolly windows too, if someone made the software), and if the software doesn't exist, i'm pretty sure my friend could make it if he wanted to.