In Jin Chi was pretty good. Masamori Tokuyama was a good champion from North Korea that fought out of Japan. I don't know of any Chinese boxers, but there are a few picked to medal in Beijing.
Look for China's Zou Shiming to make a splash in the professional ranks following the Olympics. Boxing is slowly becoming more popular in the country and due to China's immense population, you could expect world champions to start emerging within the next 10-20 years. Who would've thought 20 years ago during the reigns of Tyson and Jordan that in the future, the Europeans would have a vice-grip on the heavyweight division while one of the best players in the NBA would be Chinese? The same applies for boxing in China. Who knows, maybe in the year 2028, there will be 4 Chinese heavyweight title holders in the division... I for one would not underestimate China's potential to achieve that.