I doubt XINKAI is building Sprinter in its factory. In China foreign automakers are allowed to have only two auto-making joint ventures in China. Daimler-Benz already has two such Chinese ventures - Beijing Benz and Fujian Daimler Automotive.
On the website the Daimler badging on the vehicle is clearly "Xinkai Benchi".
So there must somehow be a legitimate tie-up between the two companies.
Perhaps it is merely the rights to sell Sprinters at Xinkai dealerships.
As for the infringement on the Lexus design, nowadays Toyota (and Honda) seem fair game in China. This model was introduced by Xinkai back in November 2007.
Xinkai Auto presented several novelties for 2012.
Besides MB Sprinter (produced in cooperation with German manufacturer according to Xinkai press release), Chinese company also started selling Vito 119 premium MPV. Also a pick-up (with same look as Higer) and new SUV were on display at Beijing International Auto Show.