The inevitable has happened.

There are only so many possible permutations of a metal box on four wheels designed to go fast over any terrain, and from the Jeep Wrangler to the Range Rover, all of them have been explored in some degree with varying levels of ability and luxury. It was only a matter of time before a group of mad engineers gathered together and said "Screw it, let's go six-wheel-drive."

Those engineers work for Mercedes-Benz, and this creation, the G63 AMG 6x6, isn't a concept, but a luxury SUV that the German automaker will build for a handful of wealthy customers.

Six-wheel-drive trucks have been in military and commercial use for decades; Mercedes made a few for use before World War II, and its commercial division has supplied a 6x6 version of the old Gelandewagen to Austrian forces since 2011.

But that truck features a bare metal cabin and power from a 185-hp diesel. The AMG engineers swapped the drivetrain from the G63 AMG, featuring a 5.5-liter, twin-turbo V-8 good for 536 hp, mated to a seven-speed transmission, good enough to hustle the 8,300-lb. juggernaut to 60 mph in about six seconds. Inside, there's room for four passengers to ride in a tableau of luxury, from the quilted white leather seats and carbon-fiber accented dash to the bamboo-lined cargo area.

As for the six wheels, they're not just for show. AMG splits the torque 30/40/30 among the axles from front to rear for maximum traction, with locking differentials for all 37-inch wheels; the 6x6 can ford water more than three feet deep and its 52-degree approach angle means it will climb most anything short of a sheer cliff face. For desert travels, the tires can be inflated and deflated from a panel in the cabin.

According to Autoweek, Mercedes plans to build about 20 to 30 of these behemoths starting in October for a price just below the $457,000 AMG will charge for an all-electric SLS, and if you have to ask about miles per gallon, then clearly you don't own enough oil wells to afford one.