You mean, like, I dunno, uh...
http://www.telegraph.co.uk/news/new...oxx-in-the-running-to-play-Frank-Sinatra.html
In the case of Jamie Foxx and Frank Sinatra, a better comparison then MLK would be, oh, Ray Charles. Given a little golden man Foxx reputedly has that's too good of a comparison to miss.
C'mon. Just ones I'd like to see arguments about racial casting that invoke equivalent examples.