Xinhua news agency carries a story with a lot of figures on World of Warcraft gold farming in China. An interesting point is that since half of WoW’s 6 million players are now Chinese, farmers are increasingly able to make a buck in the domestic market in addition to the North American, Korean and European servers.
According to the article, 100 gold sells for approximately one USD on Chinese WoW servers. For comparison, a quick browse through English language gold shops shows prices of around 2-4 USD for European servers and 10-20 USD for North Americans.
I’ve often heard it said that the next up-and-coming gold producer country after China is Indonesia, though no data probably exists.