[cweagans]

This looks incredible and very similar to an idea that I was kicking around a while back. Please email me (see profile). I'd love to contribute to this.

In particular, something that would widen access to this platform is a microphone-based input method for acoustic pianos. There are only a couple of commercial platforms that have this and AFAIK, no completely free ones have it. There are some challenges of course -- out of tune pianos, different types and makes and models sound different, variations in how the piano is mic'd, etc., but I believe those can be worked around and have some ideas about how to make it happen.