Last time I heard, DAS BOOT director Wolfgang Petersen was involved at some point for developing a highly ambitious BATMAN VS. SUPERMAN a few years ago but remained in development hell ever since.
Now there is a report that Warner Bros. has quietly developing a new, untitled adventure which would unite Batman and Superman in a live-action big screen adventure!
Not only that, the studio also tries to convince Christian Bale to return in one last performance as Bruce Wayne/Batman even though Bale himself had specifically mentioned that THE DARK KNIGHT RISES will be his last take for the iconic character. The other actor is of course Henry Cavill, who's already attached as Superman for MAN OF STEEL, set to be released in summer 2013. In case Christian Bale declines to return, the studio will seek out a new actor to play Batman.
There is a further report that two separate versions are being crafted. The first one involves Batman mentors an up-and-coming Superman, and the other one involves Superman mentors Batman. But at this point, it remains unknown whether screenwriters are attached for the project.
Whatever it is, the SUPERMAN/BATMAN project is still in a very early stages of development as the studio is currently focusing on the development of THE FLASH and JUSTICE LEAGUE OF AMERICA.