D.C. officials this week began poring over proposals from seven groups seeking to redevelop the site of the old Washington Convention Center downtown. But the final look and makeup of the site, which local leaders hope to transform into a symbolic city center, is anything but clear, say those familiar with the redevelopment efforts.

The new convention center, north of Mount Vernon Square, is to open next spring. So the existing convention center, which occupies 10.2 acres bounded by New York Avenue NW, Ninth Street, H Street and 11th Street, will be put to better use. Monday was the deadline for initial proposals, and seven teams of developers -- including top national firms and well-known local names -- threw their hats into the ring.

In their proposals, the developers seek to establish their credentials for developing the site. Their ideas on what do with the old convention center, including what mix of space will be there and what it will look like, won't come until later in the process.

"These are some of the best development companies in the U.S.," said Richard H. Bradley, executive director of the Downtown D.C. Business Improvement District, who is watching the project closely. "It's a recognition that Washington has stepped up in the kinds of things it's able to accomplish."

The proposals included information on the background and experience of the firms involved, and explained, in broad terms, how they would approach the redevelopment project.

"With these proposals, we wanted to understand who they are, and how they would attack the problems," said Stephen M. Green, special assistant to Mayor Anthony A. Williams (D).

He and others in the city's planning office plan to spend the next several months interviewing leaders of the seven development groups and visiting projects they have done elsewhere. The goal: to figure out which group has the best track record of building big, complicated projects and would work best with the local officials leading the effort. Once those firms are selected, officials will sort through some of the biggest and most fundamental questions about the site -- what should go on it, where, and with what sort of design -- together with the developers.

The city, according to its "request for proposals" issued earlier this year, is already committed to 600 to 900 units of housing, 20 percent of it earmarked for people with moderate to low incomes; 300,000 square feet or so of retail space; and open space of perhaps an acre that can serve as a town center for Washington.

But a political scramble could continue for many months -- maybe years to come -- over how to use the site and the details of what uses will be included in the development. For example, housing activists favor extensive residential space, some designated for people with low to moderate incomes; the Federal City Council, a business group, favors a music museum and large performing arts center; and the private developer involved may well want to include office space, which typically captures the highest rents of the various uses.

"There's going to be a lot of interests pulling a lot of different directions," said an executive with one of the firms that submitted a proposal, speaking on the condition that his company not be named. "It's still a mystery how it will all work out."

Forest City Enterprises led one group submitting a proposal; among other projects, the company developed the Ballston Common Mall locally. The Related Cos., which is currently building the massive AOL Time Warner Center in New York, anchors another development team. A third team includes EastBanc Inc. and Millennium Partners, which have done extensive retail development in Georgetown. And Hines Interests and Charles E. Smith Residential have teamed; they have built office and apartment buildings, respectively, in the area. Others submitting proposals were a team of Federal Development LLC, the Rockefeller Group Development Corp., Centex Corp. and Summit Properties; the Georgetown Co.; and New Vision Properties with Mesirow Stein Development Services Inc.