Techworld, in the glowing words of developer Giuseppe Cecchi, would be "a complete one-stop store for high-tech products," provide a 900-room Ramada Inn across the street from the D.C. Convention Center and boost the redevelopment of Washington's old downtown sector much the way Cecchi's Watergate complex did on the Potomac River shoreline.

A year ago, as the $240-million project was first unveiled, D.C. Mayor Marion Barry said enthusiastically, "Any mayor would welcome this kind of Christmas present to his city."

Now, however, Techworld has been caught in a crossfire of competing interests. Some, like Barry, see it as a godsend that will herald the renaissance of the still rundown environs around the Convention Center. Others contend that the Techworld proposal is too big and will ruin the Eighth Street NW vista envisioned in the original L'Enfant plan for the development of the nation's capital.

No one seems to object to more development next to the Convention Center. But the shape, size and design of the Techworld project -- planned for the two blocks bounded by Seventh, Ninth, I and K streets NW -- have drawn protests from the Smithsonian Institution, the D.C. Zoning Commission, the National Capital Planning Commission, the Commission of Fine Arts, the D.C. Preservation League, the Committee of 100 on the Federal City and two citizen groups.

The D.C. City Council already has approved Cecchi's request to close Eighth Street so his International Developers Inc. can narrow the street and create a pedestrian plaza. But other key design questions remain.

Yesterday, the city's five-member Zoning Commission, which has final authority on whether the project can be built, opened hearings on the proposal. The hearings are scheduled to continue Thursday, Monday and Dec. 6.

Among other things, the commission has to decide whether Cecchi's firm is allowed to build a complex that would:

*Have 165,000 square feet of space more than current zoning allows and be up to 130 feet tall, higher than some critics think city law allows.

*Include a passageway bridge starting 65 feet above the closed Eighth Street, which would provide six floors of connecting space between the two wings of Techworld. At the same time, it would limit the Eighth Street vista extending from the old Carnegie Library on K Street to the National Museum of American Art on G Street.

In addition, the commission is faced with choosing one of two designs that International Developers has submitted: one that is covered almost entirely with mirrored glass and another that has a more varied facade with glass, stone, awnings and various-sized windows.

Earlier this year, the Zoning Commission and the National Capital Planning Commission objected to the massive glass structure and asked for the revised design. But the Fine Arts Commission said it liked the glass design best, with commission chairman J. Carter Brown calling the second proposal "a distinct step backwards."

Meanwhile, the Smithsonian, which runs the National Museum of American Art, has objected along with citizen groups to the bridge over Eighth Street. Former Smithsonian secretary S. Dillon Ripley said in one letter of protest that closing the vista "would be a desecration of L'Enfant's foresight and planning."

"Surely private development can take place on these two blocks without closing Eighth Stret and bridging it over," Ripley said. "Development has steadily occurred elsewhere in the old downtown over the past few years -- as in fact it continues at this very moment -- without such extreme concessions. Major and historic street closings to attract or please developers can set a very dangerous precedent."

But Cecchi, in blunt terms, says the extra space and height and the passageway all are needed "so that the economic bottom line makes the project financially feasible. We need it for economic reasons in an area of Washington that has not proven itself."

Techworld, in Cecchi's view, would be the ultimate marketplace for computers and all their paraphernalia, telecommunication products and other high-technology products still on the drawing board.

At the same time, he says that exhibitors need large chunks of space that will be available only if the bridge can be built over Eighth Street.

At yesterday's first hearing by the Zoning Commission, Cecchi presided over a highly orchestrated slide show supported by a string of witnesses who said they have told Cecchi that he should not build the project if it does not include the extra space and bridging that he wants.

Stephen B. Goldstein, a commercial leasing official, said, "The importance of a trade mart environment is in being able to shop without leaving the building. They must be able to locate on large floors."