I think Huck believes if he can damage Mitt enough, he can overtake him for #2 in polling, making him the favorite for Juan's VP slot. He probably knows Romney wouldn't want it if offered.
All the butt-kissing and hugging last week aside, Rudy's campaign was so thoroughly screwed up he may have blown any chance to be McCain's running mate.
Thompson is the likely veep pick. There was never any chance for Rudy, he doesn't bring any voters McCain doesn't already have.