I'd go with an unknown (A real huge mother, probably have to troll the gyms) that can fill out a comic accurate costume and go for a hardcore comic adaption like Sin City was. Not to say in that style, simply bringing comic to film in accurately.
Nolan's take is great, for a more realistic based in our world Batman. Now I want to see us taken into the comic world. Batman doesn't wear armour much at all, he doesn't need it, he is just that damn good. Characters like Zatanna or Ra's al Ghul can be shown as they are in comics. immortal or even magical.
Think The Animated Series only live action and not stylized in the forties.
You need a very big guy to be Bruce Wayne.