I'd like the idea of P2P mobile phones, no service provider required. Phones connect directly if in range otherwise they hop via other phones to reach their target. Phones that are hopped through get paid a fee for acting as a relay. So you earn while acting as a relay and spend when making calls that need to go through other phones. I'm not sure if this could work with bitcoin, the main question is "can a phone acting as a relay be sure it will get paid?" It can't wait for confirmations, that'd not work. So can it work with bitcoin?
good in basic theory. but in practice, some have alrady tried this. here are some issues found
some people thought about sing bluetooth to connect to people locally. the issue is that with mobile phones. people walk around. meaning it will keep dropping every time people using the network move more then 100 metres apart.
another proposal was people setting up their own cell antennas. this issue is with the eventual solo-owners(thousands of people independent).. would start to become a pool. where only a few people own many masts.. much like the mobile network today