PirateBox-based internet?

Most of us have probably heard of the PirateBox in the last couple of days. (In case you didnt: [wiki.daviddarts.com]

I saw a comment somewhere that you might even be able to inter-connect those boxes. (could be lifehacker, not sure) Could that hypothetically mean that you can set up your own "grassroots internet"?

Anyone you'd want contact with would have to be connected to the same network of course, but if it's something that grows really big, then you don't need isp's etc.

Problem of course is inter-continental contact, but are there any other things which would make this not work?