We are expecting the first 28nm graphics chips from AMD to appear in 2H 2011, of course in case that TSMC gets the grip of the new 28nm process and doesn't run into any serious issues with the big process transition.
We’ve read a few rumours that Southern Islands can come in first half of 2011 and we can now confirm that this is highly unlikely. TSMC hasn’t taped out any 28nm AMD parts and even if they did, the production won't be ready until second half of 2011.
The 28nm manufacturing process is a big milestone for graphics as it will let graphics manufacturers to squeeze in even more transistors (Like three billion is not enough ed. ) achieve higher clocks and get significantly more performance at the same of lower TDPs.
The good news is that 28nm chips are still scheduled for 2011 and by this time next year there is a good chance we will have 28nm graphics from both ATI and Nvidia in the stores, provided all goes well for TSMC. Southern Islands might also be produced at Globalfoundries, but at this time we are not aware that GloFo is actually working on 28nm graphics.