The Justice League: Mortal movie they were planning in the mid/late 00's that had Common as Green Lantern, Arnie Hammer as Superman, DJ Cotrona as Batman, and I think Jessica Biel as Wonder Woman with George Miller directing.
Basically what happened is there was some friction between them attempting to launch this while Nolan was still cooking his trilogy. All these people were cast and director hired before TDK even came out. Nolan and Bale were kinda side-eying them, wanting them to wait until they were done cooking before launching another Batman in movies.
But then TDK dropped, crushed the buildings, changed how superhero movies were viewed across the board, and they fell back and decided to focus on individual properties. Then the next year Marvel kicked off Ironman and started building the universe and DC went from ahead of the game to WAY behind.