Last time around Mark Sanford seemed like an obvious VP pick but was barely mentioned--we later found out why. Likewise on the Democrat side, why Bill Richardson never got selected.
I feel like Romney has got to go with vetted choices. The media will have a field day with anyone who’s not completely vetted. That makes Bush the obvious choice. He’s been vetted every way imaginable. But Daniels and possibly Portman might also be sufficiently vetted. Christie has been vetted, but I don’t think we need someone who’s penchant is to insult people in the crowd for saying dumb things. For the most part, your Pres. candidate wants a VP nominee who melds with the crowd and is not controversial. Also someone who looks Presidential in a debate with Biden, but that won’t be hard for any of these guys.