Most of the new Nvidia 28nm mobile parts are Kepler based but some lower end chips will have its Fermi roots and more importantly - they won’t ship until 2012. The exact date is still uncertain, but we expect to see new mobile parts with the introduction of Ivy Bridge 22nm architecture.
The aim is for the Maho Bay platform to get its 28nm Nvidia chips and continue the good transition of Optimus graphics. The possible launch timeframe is going to be set by Intel, and we hear it will happen either in March or April of 2012.
The production of mobile chips starts in December at the latest, which means that these chips have been taped out for a while now. However, 28nm is currently not doing as great as some companies would make you think, as the yields are not good.
Kepler desktop version should also come in 2012, probably around the same time.