Seventeen months ago a handful of Fairfax County's most powerful developers and zoning attorneys sat down in a Marriott Hotel with some ordinary citizens to plan the future of the county's "last frontier": 5,000 acres of undeveloped land west of Fairfax City, primed with sewers and highways.

The task force had a "unique opportunity," its chairman said that day, to shape what could become the cultural and economic center of the county. The task force also had the opportunity to recommend decisions that would increase by millions of dollars the value of land held by several of its members.

After 17 months of weekly and biweekly meetings -- 12 months more than originally hoped -- the task force came up with the kind of plan the landowners said they had wanted all along. If the County Board of Supervisors accepts its recommended changes to the county comprehensive plan, the proposal could increase several fold the $2 million value of 675 acres owned by task force member John T. (Til) Hazel and his partner, the value of 80 acres owned by task force member Jack Carney and that of land held by several other task force members.

The task force wrangled, parcel by parcel, over how many buildings to allow on each piece of land -- in effect setting the value of those properties. Participants compared those sessions to an encounter group or a jury room. Chairman Michael Horwatt told members repeatedly that only a plan supported by the entire group could win approval of the board, thus making all their work worthwhile.

When they totaled the results of their months of work, several citizens were shocked to discover they had approved twice as much construction as the task force had originally set as a goal. "The landowners got all that they wanted," said task force member Henry E. Strickland Jr., who was on the losing end of the task force's final 20-2 vote.

"Hank cannot get out of the pettiness of viewing this as some kind of war, that developers have to be on one side and everybody else on the other," Hazel said. "Jim Rouse didn't make Harbor Place in Baltimore happen working in that kind of atmosphere."

The plan, which will be presented to the board Monday, pleased most of the citizens who participated. Several citizens said the landowners and professional planners representing the county infected the rest of the task force with the excitement and challenge of building an enduring monument, so that citizens with no specific stake ended up sharing the landowners' vision.

"It wasn't just a case of developers versus citizens in the immediate sense," one member said. "I think a number of people viewed themselves as having a part in creating something new, and they started to take a proprietary interest."

The supervisors appointed the task force to plan the future of the county's last prime virgin land, before fast food joints and subdivisions did the planning for them. Knowing that developers have always had their way in the county, whether through politics or in Virginia's sympathetic courts, the supervisors decided to include developers, builders, zoning lawyers and real estate dealers in the planning process from the start.

The task force came up with a vision of an "urban village" of homes, offices and stores rising out of the woods and meadows that lie strategically between Rte. 50 and Interstate Rte. 66. Its plan allows more stores and offices than exist at Tysons Corner -- and nearly one-third as much nonresidential construction as exists in the entire county today -- but only if landowners promise architectural quality and public amenities like roads and parks as well.

The task force also asked the supervisors to establish a review board to screen development plans and advise the county on whether those plans include, for instance, enough roads and parks. It said the review board, like the task force, should include area landowners. To take a "strict conflict-of-interest approach," the report suggests, "would eliminate many knowledgeable persons who are committed to the objectives of the plan."

The landowners stand to gain millions of dollars if the county allows major development in place of single-family homes, as currently planned. County officials believe the county will gain if landowners provide an economic and cultural center for Fairfax that would generate tax revenue and give the 400-square-mile county the urban psychological focal point it lacks.

"There was an initial recognition that there would be intense development there," recalled Virginia Del. John H. Rust Jr., who served on the task force. "What we were trying to do was not stop development, but make sure that when development takes place, we have the capacity to deal with it."

Those who did not share that initial vision, several participants said, dropped out early or were pulled along by the momentum of planning something new. Joseph Trincellito, for instance, questioned the grand development plans at an August 1980 meeting.

"We want a place where I can get my car to work in less than two hours . . . where I am not afraid to have my children walking the street," Trincellito said then. "Basically I don't think a lot of people out there care whether the county has a center."

Several months later Trincellito, a federal official and resident of a nearby subdivision, stopped going to task force meetings. "Large citizen groups like that," he said this week, "especially when they're so heavily loaded with property owners, have a tendency to come up with what the property owners wanted in the first place."

Jean Packard, who nurtured an antigrowth image as chairman of the Board of Supervisors from 1972 to 1975, disagrees. "I think we came up with something pretty remarkable," Packard said. "If they had put up single-family houses, they would have made out like bandits and the county would have gotten nothing in return . . . He Hazel stands to make a lot more money on it, but he will also contribute a lot more."

Cress Malkerson, who teaches economics at George Mason University, does not believe anyone was buffaloed. "We had articulate citizens out here," she said. "It's not a bunch of ditchdiggers trying to deal with the developers."

But Malkerson said neighborly concerns about traffic and pollution often faded beside the challenge of creating the "urban village." "It's a human tendency," she said. "You're going to build something, you get wrapped up in the process."

And when the final plan allowed more buildings than Malkerson and some other members believed wise, she said it was too late to reconsider. "I think there ought to be a very detailed review of the parcel-by-parcel assignments," she said. "But the committee was maybe emotionally unable to do that, having once gone through that wrenching process."