2. Knights End
With Rises having taken a good page out of the Knight Fall story arc, it seems like there's a page or two from the culmination of that same story that could be used for another movie. While the following notion might work better as a 5th movie in the set, it could still be done as a 4th. That idea of course would be that the new Batman might be unfit for the job. Robin John Blake (who has a similar name structure to Jean Paul Valley with three names being stated if you wanted to go that route) has had a troubled life and mentioned his anger and temper a few times. Maybe he'll turn out to be too aggressive and violent to be the right man for the cape. If Bruce were in Europe and got word that "The Batman" was killing people or even crippling them, he might feel it necessary to react. While it's not necessary that he put the suit back on, Bruce might have to fight with Robin's version of Batman to stop him from causing anymore harm. The romantic tension that this could create with Selina Kyle might make for an interesting choice as well. If Bruce has to choose between his lover, who at this point could even be his wife or setting right the mistake that he made it could be a great choice to see unravel. Even if Blake isn't a new Batman, but is causing trouble as Robin, it might still be necessary for Bruce to step in. A "Batman vs. Robin" movie could end up being the greatest 'vs' movie that no one ever expected to see. It would be rather interesting to see how it all flows out, because Nolan has shown us that the best of the comics story lines can be used to tell some great movie story lines that stand on their own feet. Speaking of other comics story lines that could be adapted in dynamic new ways...