Apparently Matthew Vaughn already turned it down
Am told the Vaughn discussions were touch and go, and sources close to the director said he won't be directing the movie. Let's see if that holds true. It wouldn't be the first time Vaughn has flirted with the X-Men franchise. He got far down the road on replacing Bryan Singer as director of X-Men: The Last Stand, but that also fell by the wayside. Fox continues its search, talking to a strong list of directors that includes Timur Bekmambetov, Louis Leterrier, David Slade, Daniel Espinoza and Carl Erick Rinsch. A decision will be made next week on the director with an eye toward a late summer or early fall start.
Out of that list, I'd vote for David Slade, who has directed the very smart, edgy thriller Hard Candy
and the horror film 30 Days of Night.
His next film is (gulp) The Twilight Saga: Eclipse
, which actually doesn't look half bad.