I have seen some presenters with power point in mirrored monitor mode use their mouse as a pointer to point out items on their slides.  Is there any way a secondary mouse could be used to drive a pointer that is limited to the presentation screen so this ability could be preserved with the additional advantages of going multi monitor?

I have no idea how this ability could be realized. I'm very skeptic if there is any real application using this ability.

I found a way to realize this at least on Linux.  I am not sure if it requires any special programming on the program end of things but it would be good to support this feature as it will be merged with the main linux x.org soon.  It is called Multi Pointer X.

Here are some videos from Google video that demonstrate it.  The sound isn't the best though and there isn't any talking so just mute it.

http://video.google.com/videoplay?docid=-1250196818238702520&q=multi+pointer+x+server&ei=GIAkSIPBLYTmrQPi9O3JCw

http://video.google.com/videosearch?q=multi%20pointer%20x%20server&ie=UTF-8&oe=utf-8&rls=org.mozilla:en-US:official&client=firefox-a&um=1&sa=N&tab=wv#

http://video.google.com/videosearch?q=multi%20pointer%20x%20server&ie=UTF-8&oe=utf-8&rls=org.mozilla:en-US:official&client=firefox-a&um=1&sa=N&tab=wv#

I've heard about MPX. Now I better understand what's on your mind. As I see it this feature would consist of low level, platform specific code. Certainly something in a compiled language (C or C++). Not sure if there will be bindings for python.

According to phoronix MPX will be merged with the master at x.org possibly in time for x.org 7.4.  I think the program would just have to configure the program to accept multiple pointer inputs.  I would assume that they would come out with python bindings also but I will check on that.