I'm happy to jump on the free internet bandwagon as broadband becomes cheaper (compared to what is was when these projects started anyway). I was actually toying with the idea of doing this with
my network in Marlborough anyway as our gear comes with such features as standard issue but if we can get the whole country involved I really think such a service carries significant potential.
I have had completely random requests before from visitors to the town who have picked up my network in the hope of obtaining internet access. I set it up for them on an arragement basis while they visited and it worked well. Obviously this shows there is potential for such a project.
Here in Marlborough we don't exactly have an overwhelming population abuse probably isn't as much of an issue here so we could get away with it.
The gear we use is from
Mikrotik and has hotspot features, etc built in. The idea I originally had in mind was to allow 128/64k internet access to anyone who logged on at a maximum of 50MB per MAC address that associated. Some basic keyword filtering to block bad stuff where possible and feed the thing off my home ADSL connection.
If you manage to get a solution going I'd be happy to help test it and provide access on my network.