Well, Batman is supposed to be monthly ongoing story with no end in sight, with the possible exception of old man Bruce tutoring some young rapscallion in a jetpack future. And Catwoman and Batman have been married before in the comics; a theme that appears to be repeated in the New 52. Lots of writers have focused on the idea of Batman and Catwoman having a fairly deep and possibly finalized relationship beyond the cowl and mask. It's also all but confirmed that they will be aware of each other's secret identities well before the final battle, one of the hallmarks of a more serious Bat/Cat relationship (and one of the easiest ways to tell the new comic Catwoman has a more shallow relationship with Batman. One of the more...subtle clues.)
And as fun as big teases are, I don't see anything inherently wrong with the possibility that Catwoman and Batman hook up on a permanent basis at the end of TDKR. Provided, of course they are both still alive and not at odds.
Yeah, I honestly don't see Catwoman killing Bane either. I figure Bane will either die when his mask breaks, slowly but surely, or someone else like Miranda Tate stabs him. But first he must be absolutely defeated and broken by Bruce Wayne. If someone else makes the kill-shot, Gordon, Foley or Blake seem just as likely as Catwoman.
Speaking of Gordon, we have seemingly no information on the fates of most of the supporting cast. I can see Alfred being killed by Bane in front of Bruce as the final straw before Bruce climbs out of the pit, and that would explain why we don't seem to have any confirmed Alfred action post-sewer fight. And if someone's going to make a heroic sacrifice, Gordon would fit the bill pretty nicely: The old guy who owes something to the hero decides to thank him by giving him a future.