I posted this in a different thread a couple weeks ago, but it's more relavent to this topic.
Basic Plot - With the cops and the mob (most likely) hunting Batman, it's not that hard to imagine that the GPD and the mob could possibly work together to take him in. Many people in the GPD now believe that Batman killed several of their fellow cops, so it's not hard too assume they would break the rules for revenge. Unfortunately for them, this IS Batman we are talking about, the same guy who took down a force of nature called the Joker that neither the police or the mob could control. Basically, they need help. They need get somebody of equal skill, intelligence, detective savy, and personal drive as Bruce Wayne. Enter...
Bane: Hear me out. Forget about the venom, and forget about "Knightfall." DEFNINATELY forget about Batman & Robin. Bane is simply an assasin, with a world-class reputation for those people, like the mob, who would need an assasin for hire. He has olympic level atheletic ability that is enhanced with your everyday steroids. He is also brilliant. Smarter than Bruce even. Think of an un-insane Joker, with an IQ of 300. He is hired by the mob and, off the books of course, the police to remove Batman. Gordon gives Batman the heads up, and Bruce/Alfred/Fox do their research on Bane. Bruce realizes that if anyone were capable of finding him and killing him, Bane is the man that could do it. However, this IS a Christopher Nolan movie (I hope!), and there must be twists...
Un-known to Bruce, the mob, and police, however, is Bane's affiliation with of The League of Shadows. In particular, the daughter of Bruce's mentor, Talia al Ghul. In my opinion, a romantic relationship by itself would not be sufficient enough to tie Bane with Talia and TLoS. But, what if Bane was Ra's' first student/"heir apparent", just prior to Bruce? He could have gone through superior training than what Bruce had gone through. He could have also failed Ra's in a similar way that Bruce had. Say, for instance, that Bane was too good of a student for Ra's to handle. Bane could have tried, and failed, to kill Ra's and take control of the League from him. Upon failing, he manages to escape and takes up a new identity, while still being tied romantically with Talia.
With Ra's and much of TLoS now dead at the hands of Ra's "true" heir, Bruce/Batman, a situation is created with TLoS and Bane very similar to that seen with the mob and the Joker in TDK. Talia, the interm leader of TLoS, wants to avenge her father and finish the job he started. Bane learns this, and manipulates Talia into thinking that wants to help her. His true motives, however, are to remove Talia and take control of TLoS and, of course, to break the man that became Bane's replacement to Ra's: Bruce/Batman.