There are hundreds of thousands of expatriates who live in China, but the vast majority are there temporarily. There are businessmen there on assignment, students committed for an academic year, Peace Corps and VSO volunteers, young English teachers, freelancers, and the odd vagabond. If you count only those who live permanently in China, with no immediate plans to move back to their home country, the expat population is far smaller. Outside of the major cities, it is rare to meet expats who have lived in China for more than five years. Even in Beijing and Shanghai, long-term "lifers" are not common.
But they do exist, and in this week's episode of This American Life, Beijing-based journalist Evan Osnos profiles one of Beijing's most noteworthy foreign-born residents, Kaiser Kuo. The whole episode is worth a listen.
Along similar lines, Stan Abrams has an excellent post discussing expat assimilation in China. And finally, here was my own less serious attempt to tackle the subject back in 2009.