It's quite interesting that Ron Paul and Mitt Romney are not going after each other - both are directing their fire at Newt. What's in it for them?
Mitt clearly benefits by not antagonizing Paul's supporters, where passion and loyalty runs high. In the General election, he's going to need them, and the Tea Partiers, too. Both dislike him, because he's an establishment insider. But if he gets Paul on board, that sends a powerful signal to both those groups that some sort of change is inevitable. Paul is in his 70s, and so this would be a chance for him to put his stamp on something in the years left to him.
So which cabinet post would Mitt offer up, hypothetically speaking? There's quite a balancing act that has to happen:
1. No scaring the establishment, which means that State, Justice, Treasury, Defense, and (sadly) Homeland Security are out. Too much boat rocking in places where they want the status quo.
2. It has to be important enough to attract Paul and his supporters, which means that Interior and the like are out. Agencies that have grown quickly and intrusively over the past 10 years in particular seem like they might benefit from a Secretary Paul.
So which might fit the constraints? Health and Human Services comes to mind, as the Obamacare legislation vests huge power in the Secretary - he could gut the bill like a trout.
Feel free to leave your suggestion in the comments.