Velvet Goldmine is one of those movies that is part musical, part not musical- the songs switch from being recordings, to concert performances, to dream sequence musical numbers, and back and forth. It would be nearly impossible to do onstage, and it would undoubtedly be a mess if it were attempted, but I'd probably still go see it, especially if, say, Adam Pascal played the David Bowie/"Brian Slade" role.
Oddly enough I just saw this movie a few weeks back and had a hard time making sense of it outside of the general plotline. Not sure what it could be onstage save for resembling one big acid trip, but I'm game.