Beijing's 2009 GDP (PPP) per capita: $17,063
South Korea's 2009 GDP (PPP) per capita: $27,978*
People always assume that China is converging to the United States and Beijing is converging to the major metropolitan areas around the world. If South Korea is a better model, China might be closer to finishing convergence than most people think.
*Both of these numbers are from Wikipedia, and the IMF in the case of South Korea's. A more apples to apples comparison would use Seoul's GDP per capita, but this number has been difficult to find. Calculating it using the assumption that Seoul is almost 22% of the Korean economy leads to a very similar number, about $28,500 (PPP).