Addendum to previous: Just as a wacky, way-out-there possibility, consider Maine Republican Senator Olympia Snowe. She's a highly influential Republican moderate, with the advantages that would bring; and she's served on the Senate Armed Services Committee. And all the women who wanted to help Hillary Clinton break the glass ceiling would have a chance to help Snowe break it instead.

I don't think it's likely, but hell, you never know. (Actually, I wouldn't be surprised if McCain picked Snowe in a bid to poach some of the feminist vote.)