There have been more SW Musical adaptations in the last few years.

Sometimes artists produce something related and Lucasfilm gets wind of it and they bring those people into the fold (the forthcoming SW comic art book) or smaller things like:

http://tcritic.com/archives/a-new-hope-obamastar-wars-spoof-now-available-as-a-t-shirt/

I wrote about A New Hope the poster from Ironic Sans a couple of weeks ago and mentioned that it was not a T-Shirt yet due to fears of Lucas Film retribution, well I’m happy to tell you that they are now being sold through Zazzle and with Lucus Film blessing