Don't think I'm not aware of the irony of posting a news story based off a Nuke The Fridge link, but there it is: according to sources in contact with the website, Christopher Nolan may well be planning a Director's Cut for the Blu-Ray release. Who their sources are I have no idea, but it actually wouldn't be unprecedented - costume designer Lindy Hemming told GQ recently that there was a whole sequence on Bane's origin that was filmed but not used in the movie. In addition, Nuke The Fridge states that there are new scenes with Ra's Al Ghul (Liam Neeson) that were filmed as well. They state that the total scenes would add another thirty minutes to an already pretty long movie.
Nolan isn't known for Director's Cuts. From what I understand he has final edit on his movies, and there's rarely even deleted scenes on the video releases. But for THE DARK KNIGHT RISES, it could be possible - some of the scenes in the third act seem awfully truncated, even through the bloat, and Nolan might have edited his movie in a way to keep it under three hours. I still consider this unlikely - Nolan is fairly meticulous when it comes to his movies, and I doubt he'd throw that out for THE DARK KNIGHT RISES.
But, the fact is that there are scenes that didn't make the theatrical edit. Whether or not Nolan thinks that they would add to a Director's Cut obviously remains to be seen, but they are out there. Pacing is essential to Nolan and how his movies work, and it's possible that either he didn't want to muck up the theatrical release with these scenes, or that they just didn't work in the scheme of things. Obviously this is all rumor and conjecture, so we'll see.