If you'd suspected that Mercedes' F700 show car was a preview of cues we'd soon see on production cars, there's a Schulte Design rendering to bolster your theory. The current S-Class debuted in 2005, so we won't see its replacement for a couple of years, but there's already lots of development underway. The new sheetmetal will be a full redesign, not a freshening, and the rendering depicts a car that takes inspiration from the F700, but tones the cues down a bit. The shape of the front end is very similar, with the headlights and grille echoing what Mercedes showed us in Frankfurt. Along the flanks, the arcing line at the base of the windows has been toned down. Of course, while it's a good rendering, it's still an unofficial composite image, so we should just wait and see.
Solid word on powertrains has come down from on high, though. Mercedes is looking at a hybrid version of the S-Class to compete with the Lexus LS600hL. Our current S-Class will get a mild hybrid for 2009, and there's a Bluetec Hybrid under development packing 224 horsepower/560Nm and returning 44mpg. The engines we know and love in the current S-Class will largely carry over, though we'd expect that attention to efficiency and the hybrid powertrains will be more important because of the new CAFE standards.
[Source: eGMCarTech, Rendering: Schulte Design]