This might not be the first report to predict a December arrival for AMD's 28-nm Radeons. However, it's certainly the most recent, which gives it an extra dash of plausibility. According to Heise Online, we'll see the first 28-nm Radeon GPUs make their debut in the second week of December, or possibly as early as December 6.
The German site attributes the information to sources in "business circles." It adds that folks in "board partners circles" expect a limited supply of 28-nm parts in December, allegedly because TSMC "has problems with the 28-nanometer process." Manufacturing issues at TSMC curbed the supply of the first 40-nm GPUs a couple years back, and the foundry firm subsequently scrapped plans for a 32-nm process. It could well be stumbling at 28 nm, too—but we'll reserve judgment until we can check availability for ourselves.
Here's what we know for sure right now: AMD has promised to deliver 28-nm graphics products this year, and it has vowed to work with both TSMC and GlobalFoundries on 28-nm production. Nvidia, meanwhile, plans to begin production of its next-gen 28-nm Kepler GPUs next year.