Back in 2007, George Miller was hired to write and direct Justice League: Mortal, which, despite Batman Begins and Superman Returns already being released, was not set to star Christian Bale as Batman or Brandon Routh as Superman.
The story was to be set in a separate universe, with Armie Hammer (The Lone Ranger) as Batman, D.J. Cotrona (G.I. Joe Retaliation) as Superman, Adam Brody (The O.C.) as The Flash and Megan Gale (Mad Max: Fury Road) as Wonder Woman. The story also featured Aquaman (Santiago Cabrera), Wally West (Anton Yelchin), The Martian Manhunter (Hugh Keays-Byrne), Maxwell Lord (Jay Baruchel), Talia al Ghul (Teresa Palmer), Iris West (Zoe Kazan), Alfred Pennyworth (Stephen Tobolowsky) and John Stewart/Green Lantern (Common). The plot was influenced by three major comic book arcs, JLA: Tower of Babel, Superman: Sacrifice, and Crisis on Infinite Earths #8.
Production never got under way, due to the Writer's Guild of America strike in the fall of 2007, a budget that was escalating past the $200 million mark and changes that were made to Australia's film tax credit system.
to read the full 128-page screenplay (you have to sign up for a free 2Shared account to do so), and to read Superhero Movie News' review of the script.