bowman, it's called db.etree.org, which hosts md5s of circulating shows for jam bands that allow trading of their music, i.e. Grateful Dead, Phish, etc.

As for bands that don't specifically allow such trading, it would probably make sense for a fansite of each band to post md5s like that. But someone has to set it up, spend the money, etc. Etree would be the model to follow though.