Here's what's stupid ...
If he walks, he walks with a $20-million-per-year buyout of the 4 year contract years remaining.
If he goes to Fox, NBC must pay the difference in what he is offered by Fox. If I was Murdoch, I'd offer him a dollar, and let NBC pay the rest.
He doesn't need the work, not for a severence package like that. Is he holding out? No, I don't think a development plan with NBC, even, would do it -- but maybe the Fox deal and an HBO deal might have merit.
I think NBC would want Leno back in late nite with Conan's already losing half the audience. However, Leno knows that "Tonight" is more than a 30 minute "franchise" and I'd be surrised if he took it. He may just take his $20-million for one year if that's what it was,) and go do stand up for awhile, then move to ABC. Don't think he'd be the draw Conan would be on Fox.
I think Conan goes to Fox with a development deal and the same deal he got from NBC, with the Peacock paying for it, and Fox picking up the development deal. Conan could become an owner of the syndication rights of such a project, including a late night show, ala Carson and Letterman.
NBC is in deep voodoo. They have to pay up one way or the other.