I'm well aware it's a rebadged holden, most of their work took place inside the car on the chinese Park Avenue. But there's numerous other Buick's in china that are only avalible in that market. Some are just slightly tweaked imports, others like the Invicta concept were done totally by GM Shanghai.
The US will be getting the Statesman, even though the G8 is now dead, as the new Chevy Caprice (which it's sold as in the middle east) but as of right now it will only be for fleet sales in heavy duty 9C1 police trim.
The new LaCrosse and Regal were also designed by GM Shanghai, obviously influenced by the Invicta concept. Expect this trend to continue.