Yes - we used to get regular returns from Beijing, and the Shanghai area used to be good too, along with mainland China near Hong Kong. At the time, AirNav said that sales in China were going well, but it's all gone very quiet recently.
Let's hope this is the start of a reappearance of China in RadarBox - they've certainly got enough ADS-B aircraft to keep us happy. I hope the RadarBox users aren't being blocked by the Great Firewall of China!
Rod