[NeoCZ]

I really like your description, Mike. I like combination of versioning and roles, both seems useful in different cases. Also I agree best would be to set role to "none" by default and if anyone needs different roles (keyboard, guitar, etc), they can add them for specific version of song. 

Just an idea (maybe it was said before) - would it be possible to give each version custom name? Like version 1 would be called "chords only" and version 2 "keyboard solo"?