My daughter's 16th birthday is coming up and she decided that she wants an M5. So we went looking and next thing I knew she wants it in yellow (yes I know WTF yellow?), but o.k., it's easy enough to get it painted. But, what is going to be 'difficult' is customizing it to a convertible.

Are M5's sold anywhere in the world as a convertible? If so, can it be ordered in the U.S.? I've never seen one so I'm really at a loss here. I've called a couple of places that customize cars that say it's no problem for them to do the work, however, I'd like to go the special order route if possible. Any ideas???