http://musicontology.com/ specifies some metadata, like “mashup_of” and “medley_of”; as well as the timeline ontology’s “beginsAtDuration”, “mo:bpm” and so forth.

This might fit hand in hand with what you want to achieve.

There’s also existing work regarding CC and asserting you have a license to a given work – http://wiki.creativecommons.org/Embedded_Metadata – which could easily be extended to be “CC license data + music ontology metadata”.