Thanks for pointing that out. It looks a lot simpler than I'd feared. I guess it's a natural tendancy to fear the unknown. I had this same reluctance about adding joystick support, but Rajat helped demonstrate that it's not too difficult.
I believe everything what is needed to add midi input is in the midimon.c program found at midiutilies.zip
Therefore, I've added this to the to-do list and hope to get to it someday. If others who read this have an interest in midi support, please post here so that I can get an idea of how many would use it.
This might be of help to me and would probably result in it getting done sooner. One thing that might give you some ideas is to look at how joystick support is implemented in the code. Perhaps something similar could be done to support Midi hotkeys (or at least a command such as GetKeyState to query the status of a Midi dial or key).
If someone is interested I could try to define exactly the midi part, so the developer who makes it someday (chris?) doesn't have to think about it much.
It shouldn't grow that much as long as the code uses Windows API calls and nothing huge from the C library, which I suspect is the case.
One thing that can be tested in one minute is how much the exe size grows when adding this midi support, throwing in midimon.c inside and compiling the project.
Thanks for all the info and encouragement.