I think we could have a post-apoc-style land ruled over by petty tyrants enslaving the people of their tiny isolated kingdoms through mind-numbing music into almost zombie like servitude. Players would travel about like Dogs of the Lord bringing ROCK into their hearts, inspiring rebellion and deposing the tyrants so the the people could rule themselves in a Dem-ROCK-racy.
Tyrants would have elite units of boy/girl-bands who fight the PCs dance-off style. Some of the more impressive tyrants could be corrupted former rock gods, or major players of other musical styles. Beware the opera singers!
Between kingdoms the players could fight roving bands of hip-hop gangstas, clear out nests of emos who bring the miasma of depression to their haunts, and tangle with the dreaded fanatics of the fabled evil musical god Cowell!
Things are flowing pretty well, but I stuck on combat. Or rather musical duels. At the moment each takes turn selecting which stat the combatants roll. And the loser of the roll drops a dice from that stat. But I've never been keen on the Death-Spiral. I've been looking at tennis scoring to represent the woing of the audience, and while the advantage/deuce method works, it doen't fit the theme.
I think I'll have to look at the other sectons and return to this later.