Here in Germany, we have an initiative that is devoted to exactly that problem. It is called "Freifunk" and has been deployed successfully to other countries.

http://wiki.freifunk.net/Kategorie:English

The Freifunk hackers did some amazing work to provide the needed firmware for many of the cheap standard wi-fi routers, as well as other hardware.

They are also doing good scientific work regarding mesh networks. Since they are working with real-world networks, their work usually surpasses the quality of university research. That's why nowadays many German universities are working together with Freifunk. For instance, they use Freifunk routers for their field tests.

If you want to build something like that in your town, you should definitely have a look at what those guys are doing, and I'm sure they'll be happy to assist you.