“I would say that no, we won't be considering that -- we only have one universe, and that is the universe we are presenting right now.”

Bob Harass, answering a fan question about whether there was a chance of seeing Cassandra Cain, Wally West, Donna Troy, Connor Hawke, Miss Martian etc., in a book set in the pre-New 52/Post-Crisis universe and outside the mainstream continuity. More at CBR.

Meanwhile, I’m sitting here wondering if Mr. Harass is aware of books like Earth-2, Arrow, Smallville, Young Justice, Green Lantern: The Animated Series Tie-In, Injustice: Gods Among Us, Ame-Comi Girls, Legends of the Dark Knight,  the upcoming Adventures of Superman, and a handful of others, all of which are set in different universes and therefore definitely outside the mainstream continuity.