How cool! If you have not been to Margaret Mitchell House in Atlanta, I highly recommend it! You would probably really enjoy that!
I enjoy GWTW for the story and the acting, but what sticks in my mind at the end of the day beyond that is the clothes, the makeup, the overall look of the film, etc. SO many things they could do with that in a collection! There are actually a lot of MGM films I think would work well for a MAC line.
How fun would a Wizard of OZ collection be?
POTC 5, whatever it ends up being called, is due out July 2015. That May's summer collection would be a great time to try that.