I've written before that mesh network topology on-top of standard 802.11 can make a powerful system. There is a group of hams in North Texas pioneering the way. They have been developing firmware using the Optimized Link State Routing (OLSR) Protocol. This is an IP routing protocol which is optimized for mobile ad-hoc networks.
You can read more about this groups work at their newly launched website:
This is the place for info about the efforts of a special interest group of Travis County ARES that is working on linking various hospitals and government agencies with high speed 802.11 equipment. It is an extension of the ARCHES program to establish and maintain communications ability during times of emergency when the normal channels are no longer available. The bulk of the work so far involves implementing mesh networks using the venerable Linksys WRT54G wireless router.
Here we will try to enlighten and educate you all about the High Speed Multimedia MESH network HSMM-MESH™ currently being designed, developed and deployed as an amateur radio broadband communications system. It is being used in and around Austin, and Plano Texas, as well as other sites.
Just further proof that there are still things out there to be discovered and developed in the hobby.
If you are interested in what you see on their website, I highly encourage you to check out a free Ebook titled "Wireless Networking in the Developing World" -Second Edition by Rob Flickenger.
If you are like me you'll likely be ordering yourself the printed copy.