An Amazon headquarters in South Florida could be a campus that's not confined to a single address but could have buildings across city blocks on both private and public land, a business development official said.

“I think they may have a spread-out approach,” said Bob Swindell, president and CEO of the Greater Fort Lauderdale Alliance, which is part of the regional effort to win the bid for Amazon's second headquarters.

The region has offered five Miami-Dade, two Broward and one Palm Beach county sites. The specific locations, potential incentives and other details of the offer haven't been made public, but there's been plenty of speculation on the real estate side.

Seattle-based Amazon wants to open an 8 million-square-foot headquarters on about 100 acres and create 50,000 jobs as part of a $5 billion investment.

The pool of 238 proposals in the U.S. and Canada was whittled in January to 20 with Miami on the shortlist, but that effort is regional and led by the economic development agencies in the three counties — the Beacon Council in Miami, the Fort Lauderdale Alliance and the Business Development Board of Palm Beach County.

The heads of each group spoke at an economic development forum Thursday in Fort Lauderdale held by the NAIOP Commercial Real Estate Development Association South Florida.

Amazon already is committed to opening an 850,000-square-foot mega warehouse this year with subsidies and more than 1,000 workers next to the Opa-locka airport in suburban northwest Miami-Dade.

Business incentives are difficult to obtain with South Florida land prices increasing, indicating at least some public land could be in the proposal, Swindell said after the forum.

“I think if there's land that could be put into the project that communities already control, that would defer some of the upfront cost,” he said.

Others have foreseen a noncontiguous campus at least in part on public land.

A 9 million square foot campus of six buildings spread across downtown Miami mostly on public land would be an ideal location, according to research by Miami real estate tech company Gridics LLC. It used software it developed, Zonar.City, to match Amazon's requirements with Miami sites.

The six buildings could be on the southwest corner of Southeast Second Street and First Avenue; two buildings between Northeast Second and Third streets on either side of First Avenue; the southwest corner of Biscayne Boulevard and Northeast Sixth Street; the southeast corner of Northwest Eighth Street and Second Avenue; and the southeast corner of Northeast Second Avenue and 13th Street, according to the report.

“Those six sites would not require any rezonings. If Amazon came here tomorrow, legally they would be able to build all that by the Miami 21 zoning code,” said Felipe Azenha, co-founder and director of business development for Gridics.

A prototype includes a hotel and residences, Azenha said.

The real estate is just one aspect of the bid for Amazon. South Florida often comes under fire for traffic congestion and inadequate public transportation.

Amazon has said it wants its new headquarters to have mass transit access. In response, South Florida played up the Brightline private commuter rail line and Fort Lauderdale's Wave Streetcar plan in its offer package, Swindell said.

Brightline connects Fort Lauderdale and West Palm Beach, and the Wave Streetcar is the 2.8-mile rail line planned for downtown Fort Lauderdale, Swindell said.

Another thing that Amazon proponents tout is the local connection. Company founder and CEO Jeff Bezos is a Miami Palmetto Senior High School valedictorian.

Other contenders, however, also can speak of connections to the company's founder. He has a home in Washington, D.C., and owns The Washington Post.

But not everyone thinks an Amazon headquarters would be a boon for this or other regions.

Urbanist Richard Florida, a visiting fellow at Florida International University and co-founder and editor-at-large of The Atlantic's CityLab, has called on elected officials in the shortlisted locations to ensure residents won't be on the hook for incentives offered to Amazon.

“The company would add far more value to its brand by eschewing incentives and instead working with the winner to address challenges like affordable housing and traffic congestion, which its new headquarters is likely to exacerbate,” he wrote in a column published by CNN.

Since the January announcement, South Florida has had more discussions with Amazon, and the e-commerce company is expected to make a decision by year-end.

But Kelly Smallridge, president and CEO of the Palm Beach business development board, speculates there might be a shorter shortlist coming in May or June.

“If in their search right now they come up with some winners, they may get a shortlist of maybe 10 in the next several months,” she said.