Hi Bob,
thanks. frankly now we are in the area of multi gigaherz processors in home computers I would have thought that we should be in a position to go somewhere with this problem? It is probably the only form of format changing which you can't do with your other applications; most of what you need to do with audio and midi is already covered by one thing and another already available.

Maybe the problem is commercial and the financial rewards from a potential musician market seems not enough to justify the research involved?

But I have seen Fourier Transform programs on the pc for acoustics calculations. The same math could be used for this application, I would guess.
If you've ever seen the Sibelius software for score recognition, that was ground breaking in its genius. Let's hope someone similar has a go at this problem too. That would be incredible to get a midi track or score from any audio cd...