Thanks everyone! I do things similar as stated above with drawing in the tempos. Clark, that's interesting, I hadn't thought to make the measures longer like you mentioned.
I was just wondering what others thought. I agree and think my idea is less practical and would have to be more of a performance (art) piece rather than a tool. I often work with high school students and am thinking maybe this idea of electronic baton (or something similar) could be used as a teaching tool so they can understand tempo and conducting and how it correlates to expression and movement and such. This would allow them to conduct a virtual orchestra. I don't know if VSL could be used in real-time with such a device though.
Here's a piece I found similar to what I was thinking, but of course not by tapping fingers together.
http://www.ericsinger.com/Glove2.mov">http://www.ericsinger.com/Glove2.mov "The performer uses his fingertips to "conduct" a music sequence. The rate of tapping controls the tempo as well as the volume of the sequence. Also, tapping on different fingers causes the sequence to play with a different timbre or instrument. The performance patch is implemented in Max and uses my SeqPlayer object for conducting."
Thanks again for you insight!