It really looks like all signs are pointing toward a december full-length trailer w/Mr. J. There really is no reason to reveal the joker's look in the movie this early on; the hype would not sustain to 400+ days from now.
More evidence that points to this: the scene that they filmed in chicago, with the actor playing that bank manager who slipped that they need him to do the teaser...it makes sense, because the sides that we saw earlier point to a scene with the Joker removing the mask and getting a *reaction* to his face. Not a reveal, but a reaction. Sound like the perfect teaser? That's because it is. We'll see a masked joker talking to the manager, and then when he removes the shot, our POV will be behind the j-man's head w/the manager's "OMG" reaction. "summer 2008"