Who says that green and luxury are two terms that have to be mutually exclusive? Certainly not Mercedes-Benz, which now offers the S400 Hybrid as part of its 2010 S-Class lineup.

Powered by a 275-horsepower 3.5-liter V-6 that gets a boost from a 20-horsepower electric motor, the S400 has the ability to shut down the gas engine at a stop or while coasting, but it can't accelerate from a stop on only electric power. Lithium-ion batteries are used to power the electric motor, and the hybrid engine mates to a 7-speed automatic transmission.

We had a chance to take an S400 for a quick spin in Chicago's northwest suburbs, and we found that with the exception of the hybrid powertrain, the S400 is like any other S-Class. That means it's smooth, quiet, and loaded with luxury goodies (it had better be, to justify its more than $90K price tag). On the road, the ride is smooth as glass, with nary a bump upsetting the chassis. The S400 is decidedly not a small car, and it feels like it--the car has a stout road presence.

It's also quiet. Some of that is due to the gas engine shutting off, but the S-Class platform itself is known for its lack of exterior noise. Indeed, the cockpit is so hushed that it's almost eerie.

The S400 has some interesting features, including an auto-bolster system in the driver's seat that changes the amount of bolstering in the driver's seat as the car corners. Mercedes' oft-hated COMAND audio and navigation system interface is back, but during our brief drive, it seemed easier to use than in the past. Speaking of easy, it's way too easy to engage the cruise control while searching for the turn-signal stalk--this was the biggest ergonomic flaw we noticed in our ten minutes or so behind the wheel.

There aren't many flaws in Mercedes' S-Class, and the S400 provides an option for those who want to be a little "greener." Once we have the chance to test one, we'll provide a full drive report.