Strange as it seems, that is essentially the idea proposed by Timothy J. Shepard, a self-employed communications engineer. If everyone had this you could cancel your phone line.
Signals pass from one neighbor to the next across thousands or potentially millions of links.
The vision, the basis of his 1995 thesis at MIT, led him to leave a comfortable research job at GTE Internetworking last April, and is now the seed for a startup company Shepard hopes to build. The 30-something engineer may not have to spend his own money much longer. I've solved the hardest 10 percent of the problems, but there are still plenty of issues about how to build the microwave radios and the network infrastructure. It's a classical computer science problem in the tradition of scaling large information systems, and I have a lot of faith that problem is solvable. Indeed, Shepard's background is steeped in just such problem-solving.