If you want to see what virtually unlimited resources can get you, gender bending-wise, go check the movie "Girls will be girls" ( http://www.imdb.com/title/tt0339071/
). The three leading female characters are played by men.
Before you say "I will never be that good", please remember there was a whole Hollywood crew of professionals in wardrobe, makeup, hair, lighting, voice coaching, choreography, photography and editing all pushing together to make these three ladies look the way they do on camera. Also, the three actors have been making female impersonation their specialty for quite a while already.
Nevertheless, I think it's interesting for crossplayers to see it. The DVD is supposed to be coming out this week, and it might have some behind the scenes.
On the subject of gender impersonation and movies, there are countless examples of actors crossdressing because their characters crossdress as part of the plot, but not that many where the actor and the character are of different gender whithout the switch being part of the script. Charles Busch is a "male actress" I can name.