It happens alot, whether it's Angelina Jolie playing the multiracial Mariane Pearl in A Mighty Heart, Tom Hardy as Bane in The Dark Knight Rises, or nearly the entire cast of The Last Airbender. With some exceptions, nontraditional casting in Hollywood is almost entirely a one way street, with white actors frequently filling roles meant for nonwhites, and while nonwhites are unable to do the same. In geek circles particularly, cries of "political correctness" proliferate whenever a nonwhite actor fills a role that was traditionally white, as when Idris Elba was cast as a Norse god in Thor. "Racebending" is a term that I believe originated with M. Night Shymalan's decision to hand the lead roles in Airbender, an Asian themed mythical fantasy, over to mostly white leads.
Arturo R. García looks at the latest example, in which Ben Affleck has decided to cast himself in a role based on Latino former CIA agent Antonio Mendez. Here's a graph from the UCLA Chicano Studies Research Center on the dearth of leading roles for men of color in Hollywood.
García comments:
Given Affleck’s much-hyped involvement in the Project Greenlight series years ago, where he helped make the career of fledgling directors, it’s disappointing to hear he won’t take the same chance with a Latino actor for Argos. As shown on the graph at right, taken from a 2006 study by UCLA’s Chicano Studies Research Center, shows that only Latino actors are requested only 5.2% of casting breakdowns, and get 1.2% of lead roles. Unless Affleck and company reverse course, Argos could go down as a missed opportunity on par with 21, which erased the real-life Asian-Americans who inspired the film in favor of “more marketable” white leads.
Without commenting on Affleck's motives, it's not simply that there are fewer leading roles for people of color in Hollywood. It's that even when those few roles exist, they're often just given to white people instead. And that's despite the fact that the most reliably bankable star in Hollywood is a black guy.