I've heard that, too, but what's the source? (Not that I expect her to be the choice -- for other reasons as stated above.)
US News supposedly says Romney is out. So if Whitman is pro-choice, if Lieberman won't campaign on the Sabbath, if Pawlenty would be filleted by Biden, and if KBH and McCain don't like each other, it looks like nobody is left.
check this link
Also, I saw the blurb on US News. Never heard of the reporter who is naming unnamed sources. Not very credible.