I found [1]https://en.m.wikipedia.org/wiki/Mesh_networking which has
   some existing mesh projects mentioned.  I know there are many more
   somewhere.
   The wiki page mentions for example [2]http://broadband-hamnet.org :
   "Broadband-Hamnet™ (formerly called HSMM-Mesh™)  is a high speed, self
   discovering, self configuring, fault tolerant, wireless computer
   network that can run for days from a fully charged car battery, or
   indefinitely with the addition of a modest solar array or other
   supplemental power source. The focus is on emergency communications."
   I recall these different mesh groups used to (probably still do) have
   regular get-togethers where the network traffic capabilities of the
   various systems were pitted against each other in a competition.

References

   1. https://en.m.wikipedia.org/wiki/Mesh_networking
   2. http://broadband-hamnet.org/