Hi Ken,
I thought you might want to write a paper on this, I am too backed up to do it myself, but here are some screen shots:
Picture 4 is the original video of the PPt presentation onto a projection screen.
I put this clip above the corresponding PPt jpeg.
I added color correction to add contrast and enhance the red.
Then I added Color Key, Outer Glow, then Overdrive to make the pointer more visible.
Picture 5 is a computer screen shot of the finished video.
I don't know why there isn't already something like this in existence, it seems so practical. If you want to play with it and develop it further, you have my permission and take credit for it. Folks will pay more attention to your instruction in a 'White Paper' than stumbling across it in the discussions search.
I really appreciated your comments,
Trig