Called the S500 in Australia but likely to be called the S550 here, assembling the various rumors yields a motor yacht that bests the Porsche Panamera S E-Hybrid for the segment's lowest CO2 emissions at 70 g/km (in fact, that's better than a few variants of the Toyota Prius). The big Benz will use a 3.5-liter V6 aided by one electric motor and a battery pack in the floor of the trunk, and it will do 15 to 20 miles on electric power and get from 0-to-60 miles per hour in under six seconds. The model will also get an AMG tailpipe treatment according to patent drawings, and might boast a US combined rating of around 75 miles per gallon.
Autocar notes that Mercedes-Benz has sold more hybrids than the other Teutonic luxury makers combined in 2012. If the S-Class PHEV unveiled in Frankfurt can stand up to the gossip, we can envision the trend continuing.