Two REALLY interesting entries in this LA Times blog here -
http://latimesblogs.latimes.com/herocomplex/
First, there's a nice bts picture of Tom and Erica from this season, along with this quote:
...but, man, Tom Welling, now 31, sure looks like Superman doesn't he?

I like this writer.
In the entry just prior to that one is the 3rd part of an interview with Christopher Nolan in which he pretty clearly rules out his Batman universe being able to cross-over with any other that includes other superheroes.
Nolan: I dont think our Batman, our Gotham, lends itself to that kind of cross-fertilization. It goes back to one of the first things we wrangled with when we first started putting the story together: Is this a world in which comic books already exist? Is this a world in which superheroes already exist? If you think of "Batman Begins" and you think of the philosophy of this character trying to reinvent himself as a symbol, we took the position -- we didnt address it directly in the film, but we did take the position philosophically -- that superheroes simply dont exist. If they did, if Bruce knew of Superman or even of comic books, then thats a completely different decision that hes making when he puts on a costume in an attempt to become a symbol. Its a paradox and a conundrum, but what we did is go back to the very original concept and idea of the character. In his first appearances, he invents himself as a totally original creation.
GB: That doesn't lend itselt to having him swing on a rope across the Metropolis skyline.
Nolan: No, correct, its a different universe. Its a different way of looking at it. Now, it's been done successfully, very successfully, in the comics so I dont dispute it as an approach. It just isnt the approach we took. We had to make a decision for "Batman Begins."
So, it sounds as if there ever were a Justice League, or other individual DC superhero movies, they likely won't include Bale.