When Mercedes-Benz overhauls one of its core models, it doesn’t mess around, and the next due for a replacement is the flagship S-class sedan. While the all-new 2012 S-class likely won’t make its official debut until the next Frankfurt auto show in fall of 2011, these spy shots of an early prototype roaming the roads in Germany provide a nice sneak peek.

The tack-on body panels and placeholder lighting elements on this prototype obscure many of the details that will define the next S-class, but there is plenty that the camo does not hide. The profile and proportions remain similar to those of the current car, but we expect it to have an inch or so more space between the axles on both short- and long-wheelbase models. This LWB version looks taller than today’s S-class, and the arching roofline appears to unwind over the rear windows a touch more than it does on today’s stretched S. Beneath the cladding, the body sides will have flowing contours and the sweeping fender treatment from the current E-class and the upcoming 2011 CLS-class. Unlike those models, however, the stately sedan eschews the chopped-greenhouse look in favor of a high ceiling and huge windows that remind us a lot of the slab-sided S-class of the 1990s. Well, and the Popemobile.