Great idea, but I’d actually recommend getting yourself an orchestra. Then you’ll have the fun of trying to convince a bunch of temperamental musicians of the rightness of your tempi.
The problem with just changing the tempo is that it wouldn’t change the host of other things musicians would change if they were to take a different tempo – volume, bow stroke, vibrato, etc.
But, now that I’m really considering it, it’s a lovely idea for the short term. I’m pretty sure my engineer told me such software is already in existence. I’ll ask him.
Thanks for writing.