A couple days ago Rush Limbaugh suggested that Congressman Sensenbrenner should be considered for this position. I don't know that much about him, other than he fought hard (successfully) in the Senate to get teeth in the Amber Alert bill, and he fought to get illegal drivers licenses considered as part of this intelligence legislation. He's House Judiciary Committee Chairman, but I don't know his record or history there.
He's very popular with conservatives, but not overly with any of the Democrats or moderate Republicans, from what I understand. I doubt he would be considered, especially after this whole ordeal of him going against the administration regarding immigration.