Problem with Mando is that color might match what is on screen so become unseeable. So this limits the numbers of pointer you can have.
Glyph tracking would allow better interface and even multi user. Most stick pointers to screen are round. Basically to make what I am thinking of work I need a Glyph of some form that can be placed on a round object. So allowing multi user interactive point screen built out of a web cam projector and a few fancy made sticks.
Image Glyph on a piece of paper could be used to calibrate camera to screen. Ie place known size paper at screen.
I can see other uses for Glyph detection like display machine Glyph have particular keyboard input done. So making using it more live.
Big advantage of this kind of setup. No fancy surface to build. Disadvantage pointer interfering with screen output.
I see many interesting input usages for Glyph like Glyph based remote to PVR. CPU usage is going to be key.