They started with Pringles cans and moved to ruggedized containers, but a $200,000 grant should let them expand further: In this Illinois college town from whence Mosaic sprung 11 years ago, two community wireless networkers have received a $200,000 grant from George Soros's Open Society Institute to try to affordably build out downtown Urbana.
The Champaign-Urbana Community Wireless Network has built their own hardware (using Soekris boxes, a commodity platform for community wireless groups) and their own mesh routing software. You can read about the specifics on their site. The software is open source under the BSD license.
As with many of the newer or renewed community wireless groups, having an off-the-main-grid local network is part of their goal, which was a concept originally articulated by the folks at Seattle Wireless.