My little sisters who are 14 they are twins want a moulan rouge cake with the windmill and the moon, im just not really sure what would be the best way to do it. any ideas?

do you want something elaboate or simple. if you want something simple what about a FBCT or a scanned edilbe image.

this would be a simple edible image
http://www.amazon.com/dp/B00005BJ2O/?tag=cakecentral-20

A photo of the movie poster...large enough to print out OK on a full sheet of icing...is on art.com:

http://www.art.com/asp/sp-asp/_/PD--10282841/SP--A/IGID--784908/Moulin_Rouge.htm?sOrig=CAT&sOrigID=10894&ui=7F477FD5FA9A4DED93D4CCA5C384718C#