To be honest, I'm a bit surprised at all of the negative comments I've seen regarding the "zombie apocalypse" bit. We have tried to make it clear that the zombie thing is a joke, the real inspiration and goal of the project is natural disasters and political activism. On our original wiki, those goals were listed as items 1 & 2, the zombie bit was added as a whimsical third scenario but it seemed to catch on people who were interested in our project.

In reality, we are developing Byzantium to be useful in exactly the kinds of situations you describe. We have been discussing these ideas with people who have experience or expertise in emergency situations, such as political protests (Egypt, Syria, and OWS) and natural disasters (Katrina and Port-au-Prince). We are eager to make Byzantium into a solid tool for first responders who have a need to communicate and organize the relief effort. But also, we want it to be useful to individuals and communities seeking to prepare themselves against outages.

Yes. The routing protocols we have chosen are layer-1/layer-2 agnostic. You can connect to other nodes through any physical link you have available. Dial up, satellite, HAM radio, a VPN tunnel, carrier pigeon, ...

We believe that it can be done, that it can be done securely, and that it can be done securely for iPhone users. Obviously there will always be challenges and vulnerabilities in any system this complex, but we can make an effort to address those or at least make it easier for end users to exercise common sense. We're not there yet, but we think this is a step in the right direction.

We're still having some trouble supporting MacBooks, particularly because none of the core developers own one. We'd love to help you troubleshoot the issue, as we certainly don't want to exclude Macs from being nodes. Best way to reach us is through our mailing list or in #byzantium on Freenode.

I recommend Commotion Wireless.
http://commotionwireless.net/

The great folks at The Serval Project are working on that and we're keeping a close eye on their work.
http://www.servalproject.org/

We have started on this already. https://github.com/Byzantium/Byzantium/wiki/Setting-up-a-mesh-node-without-byzantium. We will have a lot more on this in the coming months. We're heading to an International Summit for Community Wireless Networks in early October to collaborate with other mesh projects and communities on some standard for interoperability. Also, the software we're using to build Byzantium will be packaged and submitted to the top Linux distros for inclusion in their repositories, but for now it's easier to develop and test on a closed platform.