I've just got after sitting in traffic for two hours. As is often the case, my mind was drifting over a number of topics - and I started to wonder about some possible midi controller technology that may already exist but if it does I have not heard about it:
Not everyone can play keyboards in realtime, and often a keyboard is not the most suitable way to "play" non-keyboard samples. However, the technology exists for computers to take a single audio line and convert it to a midi pitch value ($10 electronic tuners do this, and there is a basic audio to pitch convertor included in Finale). I am guessing that it would not be too difficult to translate audio volume to midi volume at the same time.
So would it not be possible to create a software midi controller that takes an audio signal through a microphone from a clarinet or trumpet that converts the audio data to midi data and send that data to a sample player, or sequencer? For GPO, the midi volume data could be routed to the mod wheel CC.
With pitch shifting functionality included, a non-keyboardist could play al the samples on the instrument of their choice.
I'm guessing that the answer is that either something like this already exists - or people have tried it and latency is a problem. However, I need to be convinced that this is not a good idea!