Some of the proposals are huge in scale. One of those projects is Pedra Branca, a 10-mile-wide island off the coast of Brazil. The 700-acre plan already has 4,000 residents, 600 houses and condos and offices that house 4,000 workers. Developers are looking to up those numbers to 30,000 residents and 15,000 employees, said contractor Valerio Gomes.

There are also plans in the works to construct a 20-block downtown area with ground-floor retail. In the sustainability area, the new city will be pedestrian friendly, Gomes said, with a concentration on mixed-use, dense building.

"Malls are all over the country," Gomes said. "It's sort of a return to a small city."

Of course, the fate of this immense project rests in the hands of the global economy. "It depends on the crisis, Gomes said. "We're all in the same boat."

Another ambitious sustainable project on tap is Masdar City in Abu Dhabi, United Arab Emirates. Abu Dhabi's government is investing $15 billion in the project, which is being billed as fully sustainable. It will house 50,000 residents and use no fossil fuels.

Despite the problems in the economy, the government is still shooting for its 2015 completion, said Khaled Awad, director of property development for the project. "This project is considered a priority," he said. "It is being given all the attention to ensure it remains on track."

And even a financial institution, Deutsche Bank, is big on sustainable building. It is still planning on greening its headquarters in Frankfurt by 2010. Holger Hagge, the bank's director of strategic projects, said that the firm eventually plans to do so to all of its real estate.

"The key issue is that we commit to the responsibility," he said. "We say this is a statement--this is our headquarters."