In fact, this type of functionality is hopefuly becoming an Internet Standard: http://www.internetsociety.org/articles/moving-toward-censor...

However, Bittorrent is not up to the task, due to NAT issues. UDP NAT puncturing is not present in this stack, right? Thus how is it going through carrier-grade NATs which block all these smartphones?

Disclaimer: working on a similar thing for years Tribler Mobile.