The suggestion of a four-door Mercedes-Benz SLS AMG model stems from a series of photos filed at a German patent office, later picked up by Autoblog and Motor Authority. The images clearly show a stretched version of the SLS with an extra set of suicide doors to go along with the iconic gullwing doors.
Of course, the documents are unconfirmed from Mercedes-Benz, as the automaker gave a big "No comment" to Autoblog when asked about them. It is possible the filing was a "just in case" move to keep the door open to future possibilities given the way many exotic and high-end luxury sports cars have been moving towards four-door variants lately.
It should also be noted that the documentation accompanying the illustrations apparently went into a fair amount of detail (in German) about weight savings due to the special design of how the doors would be attached and function. With a top-dollar performance car of this nature, a unique solution to the weight problem associated with adding two more doors could be what it takes to make a push towards production.
For now, we file this under "maybe," as we will have to wait and see if any further information leaks from the German automaker before claiming that a four-door SLS AMG is heading to a dealer lot near you.