Mitt Romney appears to have narrowed his short list of potential running mates, as national Republicans announced Monday that at least four people once thought to be under consideration for the No. 2 spot will speak at this month’s Republican National Convention — all but ruling them out of contention for the vice presidential slot.

The Republican National Committee announced that former secretary of state Condoleezza Rice, former Arkansas governor Mike Huckabee, South Carolina Gov. Nikki Haley, former presidential candidate Rick Santorum, Sen. Rand Paul, former Florida governor Jeb Bush and New Mexico Gov. Susana Martinez are among those expected to address the Aug. 27-30 convention in Tampa.

That still leaves a number of presumed contenders — including former Minnesota governor Tim Pawlenty, Sen. Rob Portman (Ohio), House Budget Committee Chairman Paul Ryan (Wis.), Louisiana Gov. Bobby Jindal and New Jersey Gov. Chris Christie — in the mix.

With less than three weeks until the convention, speculation about Romney’s selection is escalating rapidly. And his campaign is doing its best to maximize the attention, taunting reporters with the prospect of news, joking about the timing and scheduling a bus tour through four swing states this weekend that could be the backdrop for a vice presidential rollout — or not.

“I’ve got some folks coming over today,” Romney told reporters Monday as he left a grocery store near his vacation home in New Hampshire. When one asked whether his house guests included Portman and Pawlenty, Romney simply laughed.

He did meet on Monday with Beth Myers, his longtime adviser who is managing the vice presidential selection process. He also saw strategists Stuart Stevens and Russ Schriefer, and Bob White, one of Romney’s closest friends and a fellow founding partner at Bain Capital, joined the group at the house. The meeting was likely to be one of Romney’s few opportunities to review the selection process in private before the Tampa convention.

Whether he has made any decisions about a running mate — or the timing of a rollout — is unclear. His wife, Ann, remains in London to watch her dressage horse compete in the Olympics. The horse, Rafalca, will participate in the Grand Prix Special round on Tuesday morning (5:45 a.m. Eastern time) — her final opportunity to help the U.S. team win a medal. It’s also her chance to qualify for the final individual medal round on Thursday.

Republicans widely assume that Romney will wait until his wife returns home to announce his vice presidential choice, making next week seem like a logical time.

All eyes on the bus

But the campaign is also fanning speculation that an announcement could happen at any moment, including on this weekend’s bus tour. The trip will take Romney through the home states of three possible contenders: Virginia, home of Gov. Robert F. McDonnell, on Saturday; Florida, home of Sen. Marco Rubio, on Monday; and Ohio, Portman’s home, on Tuesday. Romney will also stop in North Carolina on Sunday.

On Monday morning, Romney’s campaign tweeted a link to a Richmond Times-Dispatch op-ed by McDonnell on welfare reform, shifting the spotlight back to the Virginia governor, whose name had been fading from some of the guessing games of late. McDonnell and Rubio will join Romney on his bus tour in their respective home states, a campaign official confirmed late Monday; Portman is expected to join Romney in Ohio, according to multiple reports.

In an interview Sunday, Romney did nothing to stop the speculation. “I have nothing for you on the vice presidential front,” he told CNN’s Gloria Borger. “I give you nothing on that. But I can assure that by the third day of the Republican convention, we will nominate a Republican VP.”

The slow march toward a running mate has drawn immense attention to both the process and the potential nominees. Each addition to Romney’s vice presidential staff — including the hiring last week of spokesman Brendan Buck, a longtime press secretary for House Speaker John A. Boehner (R-Ohio) — has drawn out the speculation further.

When Ryan’s political action committee amended its Federal Election Commission filings over the weekend, it was a possible sign that he was preparing for a promotion. So, too, were the congressman’s unexpected cancellation of an appearance last week and news that Jindal had praised Ryan last week at a conservative conference in Florida.

For the contenders, the past few weeks have brought an unfamiliar level of attention. One day last month, Pawlenty stepped out of his Eagan, Minn., home to take the family dog for a walk — and found reporters awaiting him outside. A few days later, Portman walked off a plane at the Cincinnati airport after 1 a.m. and saw a reporter in the nearly empty terminal, watching to make sure he had actually arrived in Ohio and hadn’t been sent instead to some undisclosed location.

In Washington, Portman and Rubio are among the lawmakers whose Capitol Hill offices have been staked out by the press.

The Democratic opposition machines are already whirring as well. The super PAC American Bridge has trackers — armed with hand-held cameras — stationed in more than a dozen states, ready for deployment whenever a top Romney surrogate comes to town. The group has also released more than 1,300 pages of research on Pawlenty, Portman and Rubio.

Changing the subject

The ramped-up vice presidential speculation has worked in Romney’s favor, helping change the subject at awkward times. When the Obama campaign was hammering Romney last month over his unreleased tax returns, a rumor surfaced that Rice was under consideration to be his running mate. As Romney faced unwelcome headlines during his European trip, the campaign started sending tantalizing smoke signals once more: Myers tweeted the names of several top Republicans believed to be on the shortlist. On the last day of Romney’s voyage, his campaign released a mobile app that will serve as its “first official distribution channel” for the vice presidential announcement.

Late last month in North Carolina, Pawlenty received an enthusiastic reception at back-to-back events demonstrating two sides of his campaign trail appeal. First, the former ice hockey player held an intimate roundtable with sports parents at a Cary ice rink, after which he strapped on skates and took a few laps as the cameras rolled.

Later, in Raleigh, he had a crowd of several hundred supporters cheering at an outdoor rally in the sweltering summer heat.

He proclaimed that Obama is “all foam and no beer,” getting the kind of applause that eluded him when he was running for president himself.

As he shook hands with supporters at the ice rink, Pawlenty happened upon a familiar face: one of the reporters who had been staked outside his house earlier in the month.

“Oh, it’s my neighborhood friend,” the former governor said, laughing.

Philip Rucker in Wolfeboro, N.H., and Frances Sellers and Bill Turque in Washington contributed to this report.