Robert Downey Jr. is said to be circling the role of the Wizard. Playlist reports that details are scarce, but that the project is a prequel to The Wizard of Oz and is based on a script by Mitchell Kapner.
With Bond producers Michael G. Wilson and Barbara Broccoli putting "Bond 23" on hold, Mendes is freed up from that project but Downey Jr. has an upcoming schedule that includes Alfonso Cuaron's Gravity, Guy Ritchie's Sherlock Holmes 2 and most likely Joss Whedon's The Avengers early next year.
Last month, The Los Angeles Times reported that Joe Roth was developing a movie called Brick that delves into how the Wizard came to sit behind the curtain. That screenplay was drafted by Kapner, basing it on pieces from several other L. Frank Baum Oz books as well as his original ideas, said the LAT at the time.