Personally, I think there's a decent way to bring "Robin" into this film, although it may be a little tough. Also, I'm not a huge advocate of bringing Robin into this series, but I've got faith in Nolan doing it right. Regardless, I can't see it being too easy... But here's a "rough draft", so to speak, of how I could see it working more easily:
1- Obviously, bump Robin up a couple years... I'd say, minimum, 16 or 17 years old. The same story comes into play, however- Dick's a trapeze artist whose family is killed due to Zuccos distortion of the circus the Graysons perform for. Bruce adopts Dick with Dick almost unwilling, and becomes even more unhappy with Bruce's constant leaving.
2- Dick has some talk with Alfred (most likely, just as in Dark Victory, about Bruce's childhood and the loss of his parents), that eventually leads to Alfred saying something that (unbeknownst to Alfred) goes through Dick's head as, "This is my opportunity to fight crime and get back at Zucco!"
3- Dick creates the Robin persona, and tries to track down Batman, (whether to aid him or to challenge him [possibly due to the accusations of Batman being a criminal, and that he may have a link to finding/beating Zucco]- or even both- would have to be decided) parading around to try to fight crime. After a few meetings, Batman finds Robin to be Dick. Bruce plays this off as if he found out about it through the police/news, and "grounds" Dick, disallowing him to leave the manor.
4- During this particular story, Bane comes into play as well. Eventually comes the battle between Batman and Bane in which Bane breaks Batman's back. Gotham devolves at a moderate rate into chaos since the police force isn't very capable of operating effectively without Batman's help. The media is flooded with, "Where is Batman?"
5- While Bruce is immobile and bed-ridden in Wayne Manor, Dick takes this as his opportunity to "explore", finding the cave. He finds a Batsuit (perhaps a new prototype or a "spare" of the TDK suit?), which he takes and develops into his own suit with his own symbol.
6- When issues in Gotham go from bad to worse, the police force try again to use Batman's signal (some time after realizing that Batman may be "dead", maybe?), and here appears Dick Grayson- only this time, as Nightwing, who manages to help the police force take Bane down.
At least, that's how I see it. It could be a perfect opportunity to bring in Dick and Bane, as I'm sure some fans out there want to see.
I also had small ideas about Jason Todd and Tim Drake being brought in later as well, but we'll save those for another conversation. Let's worry about Dick first. :P