I wanted to know if any such system already exists for the average open-source user. With all of the net neutrality arguments around and with the cost of broadband likely to go up in the future. It seems like a good idea for an open-source protocol that allows standard consumer routers to operate together and form a mesh network with other consumer routers close by.
Likely possible that with enough nodes in close enough proximity and a good abstraction we could get something good going.
You could always use WDS nodes (like a repeater, kinda).
I use it in my Buffalo AirStation with DD-WRT installed (any router that can load DD-WRT would work).
www.dd-wrt.com
Not sure on the scalability of it though. And the APs would have to be in reach of each other. They could run on separate SSIDs though.
Edit: here's the DD-WRT Wiki page about WDS: http://www.dd-wrt.com/wiki/index.php/WDS