True, but I know for a fact that blacks can be bishops, cardinals, and priests. 12 years of Catholic school, and growing up in a Catholic background has allowed me to see it.
My mom is also a director for one of the diocese's, and I see black missionaries (mostly Jesuit priests) who pass through, and some are definitely colored.
Not to mention, the Catholic Church is more progressive than people sometimes think. The media portrays things a certain way, but if a person were to talk to a priest, they'd find that most that are part of the Gen X or Y (and even some baby boomers) are a lot more liberal and progressive minded than what is portrayed in the media.
A black Camerlengo is not outside the realm of possibility. Caviezel's a decent choice, but I'm sure he doesn't want to be typecast (which he already may be); Denzel could be interesting and does have charisma. Kevin Spacey might be an interesting choice as well. I think that role will be as tough as finding a Vittoria.