I just read this article on Joseph Gordon Levitt's character in the Dark Knight. It suggests that while the character isn't named Dick Grayson, he could be a similar character with the same back story, who will take over as Batman in the end. It's a long shot, but considering Nolan has said this movie will be an ENDING to the story, I think it's worth considering. Here's the article:
http://whatculture.com/film/the-dark...comment-100430

What do you think?