I noticed that the OLPC project builds into each laptop a Marvell 83W8388 chip to support a self managed WiFi mesh network. No engineering needed, Just get power to the chip, hang an antenna on it and stick it on your roof or up a tree.
The whole OLPC laptop is less than $200 now and going down. Leave out the screen, the keyboard, the memory, the CPU, and the case. What would the WiFi part cost? Could I buy a dozen for $100 and unwire my whole neighborhood, linking in to my DSL or satellite high speed Internet connection?
Maybe Google would like to arrange for the availability of a suitable chip/antenna/power-supply in a weatherproof package. Of course, everybody now profiting from Internet access, or TV, or voice communication by wire or through cell phone towers would object to the idea. After all, a single month of service on any of those would cost more than the purchase price for another node in the mesh.
If just a fraction of the nodes were powered by solar cells with battery backup, that could provide an extremely robust communication system to assist in addressing any disaster, whether man made or delivered by Mother Nature. Thus even local government officials might lend their support for part of the system and for coordinating the emergency coverage aspect of the mesh network. See, government can be truly useful in certain circumscribed areas.