Will There Be A "BATMAN 4" Once Nolans Done With His Trilogy?

So I wonder if when Nolan is completely done with his "Batman" prequel trilogy, someone else will make their "Batman" film. And would it be a sequel to Nolans trilogy or would it be a completely new film or film series?
Christopher Nolan has announced that he will end his series with the third film. And Christian Bale has also said that he only signed on for three films. So will he sign on for a fourth film, or even a fifth, or will he (like Nolan) leave the franchise completely after the third film. I personally think that if the Warner choose to make a fourth film, Nolan will return as possibly a producer or even be (like the new "Superman" film) the godfather. He'll just watch over it. But I do think that once the third is out, we'll never see Bale in the bat-suit again. I think that if the Warner comission a fourth film, they will cast a new guy for the role of Batman.
For a fourth film, I would like Warner to adapt the "Arkham Asylum" game into a film on its own. Now it would be hard, but I'm sure if they got the right director and the right writter and even the right cast, they could accomplish is perfectly. Okay, they would have to bring in a new guy to play the Joker, as he is the main guy in the game, but I'm sure they can do it.