Ben Kingsley has apparently been cast in Iron Man 3 as the Mandarin, a Chinese character supposedly descended from Genghis Khan (Kingsley is half-Indian, half-white). As Mark McDonald points out, casting against race can be risky:
Non-Asian actors have long been derided for taking on roles as Asian characters…. In an edgy essay, “A Certain Slant: A Brief History of Hollywood Yellowface,” Robert B. Ito offered biting reviews of Caucasian actors playing Asians. About John Wayne playing Genghis Khan in “The Conqueror,” Mr. Ito said it was “universally acknowledged as one of the Duke’s most wretched performances, as well as one of the worst casting decisions in Hollywood history.”
Additionally, Mandarin's ethnicity and villainy may not go over well with China's censors, who are known for demanding alterations to American films.
The Dish 