Hi there fellow musician! I am 100 percent certain that anything done in the music industry will soon find it's way in the blockchain, as it is the future of the world we are living in. Regarding the multitrack sharing, people already do it but yes, we don't have any network providing multitrack exchange. I had a similar idea but life sent me on the other path. Currently I am cleaning dust of my monitors and keyboard, assembling my mic... We shall see!