An update to the earlier piece:

Although a number of readers have suggested Peter Jackson as an obvious choice to step in for GDT on The Hobbit, deadline.com claims that this will not happen. PJ's manager Ken Kamis is quoted as saying: "Peter has and has had obligations and commitments to other films that would make it impossible for him to direct The Hobbit at this time, even if it was offered, which it hasn't been. I've been quietly working on setting up a film for him to direct while Guillermo would have been directing The Hobbit. What you saw in their respective statements must be taken at face value. All of that said, Peter and Fran's commitment to The Hobbit is total and they will do everything necessary to protect the franchise and the investment made by New Line, Warners and MGM."