China is on deck, but I don't think it will be the country. The government over there actually doesn't like the currency since there is no way to control and track it. They've actually enacted some not so friendly laws over it.
The protocol is getting better though. These farms are neat, but once BTC meets mainstream acceptance to the point where people need to be concerned about the 51% nearly all coins will have been mined, and there will be simpler and better ways to validate the BTC ledger than through the mining system.