The guys from Donanimhaber.com managed to score what appears to be AMD's 2012 mobile GPU roadmap slide that shows all the upcoming mobile 28nm GPUs that we will see next year, or rather their code names and some sketchy info.
The Gamer/Enthusiast market with TDPs over 35W will be catered to by two mobile GPUs, the Heathrow with a 128/192-bit memory interface that will hit the production in Q4 2011 and the high-end Wimbledon with a 256-bit memory interface and production in Q2 2012. The Performance segment, with the TDP ranging from 20 to 30W, will have Chelsea, a 28nm 128-bit GPU that will hit the production in Q4 2011.
The last one on the slide is the Tames GPU. This one is a part of Mainstream/Performance segment with a TDP of 15 to 25W and it should provide double the performance of the Seymour GPU. It will be also made at 28nm manufacturing process, will have a 128-bit memory interface and will go into production in Q4 2011.
You can check out the slide here.