First things first: Judd Gregg has confirmed that he's under consideration:
"I am aware that my name is one of those being considered by the White House for Secretary of Commerce, and am honored to be considered, along with others, for the position," Gregg said in a statement. "Beyond that there is nothing more I can say at this time."
Ambinder's sources tell him Gregg's not just one of many, but maybe the one:
The White House isn't commenting, but my understanding that Gregg is a leading candidate for the job, not just a regular candidate.
...The White House understands that Gregg's successor might be a Republican; Gregg understands that the White House does not object to this possibility, which is one reason why Gregg is taking the call to serve so seriously.