One likely suspect, the blunt-talking Gov. Christie of New Jersey, is scheduled to campaign for Romney on Sunday in Exeter, bringing some of the brightest star wattage in the GOP to bear on behalf of the stiff, awkward front-runner.
Of course, Christie disappointed many Republicans last year when he passed on running for president himself, but much of the yearning just transferred to wishing he would be on the ticket. There's undeniable bromance there - Christie endorsed Romney in early fall after letting the cup pass and made a surprise visit to New Hampshire before a debate to confer his blessings. Romney visibly glowed.
In addition to the chemistry, Christie could conceivably help Romney carry New Jersey, which no GOP presidential candidate has done since 1988, and would be a superior surrogate on the national campaign trail. Of course, he could also accomplish both those things remaining in his current post in Trenton.
Christie is leaving the door open. "If Gov. Romney comes to me and wants to have a talk about that, we'll have a full conversation about that and then Mary Pat and I will make that decision about what we want to do with our future," Christie said in a Fox News interview before Christmas. "But my view is, I think if you fast-forward the tape to a year from now, I think it's going to be President-elect Romney and some other VP-elect - and Chris Christie, the governor of New Jersey."
Christie repeatedly has said he would not be a good second fiddle. "Do I look like somebody's vice president?" he said at one point.
Another name very much in the mix: Florida's junior senator, Marco Rubio, a charismatic Cuban American with nine years in the state legislature on his resumé, including a term as speaker of the Florida House, and strong support from tea party activists. Presumably Rubio, 40, could help carry Florida, which will be as pivotal as ever, and also appeal to Latino voters, the nation's fastest-growing minority group, which has been drifting to the Democrats in a big way in recent years.
But here's a Pennsylvania angle on the veepstakes: Some handicappers even think Rick Santorum might be a good No. 2.
The former Pennsylvania senator has right-wing street credibility and is strong among evangelical Christians and other social-issues conservatives - important parts of the GOP coalition. As the grandson of an immigrant coal miner, Santorum also is a Northeasterner with a working-class sensibility (Did you hear him from Iowa on Tuesday night, describing his grandfather's hands?). Pennsylvania is a swing state, and, until his landslide loss to Bob Casey in 2006, Santorum had demonstrated strong appeal to economically stressed but culturally conservative whites, a key voting bloc.
"Romney will need a social conservative, a running mate who can mix it up and won't wilt under the pressure," said political scientist G. Terry Madonna of Franklin and Marshall College. "Does that sound familiar?" Santorum would also offer Washington experience, without the baggage of being a current member of Congress, plus credentials in foreign affairs, Madonna said.
Of course, Santorum comes with some downside. As college students at a campaign stop in New Hampshire learned Thursday, he never flinches from arguing against abortion or same-sex marriage. And media accounts are starting to pour forth about his hefty post-Senate income from some of the same powerful interests he dealt with on Capitol Hill.
But for now, none of that prevents a Romney-Rick ticket from being part of the buzz - in the hive mind.
Contact politics writer Thomas Fitzgerald at 215-854-2718, firstname.lastname@example.org, or @tomfitzgerald on Twitter. Read his blog, "The Big Tent," at www.philly.com/BigTent.