From the video at http://vimeo.com/18443073, the motor is on one side, the gearbox is in the middle, and the power inverter is on the opposite side.
My question is simple, but might not be so easily answered. In ICE vehicles, a differential would take the output of the gearbox and connect it to the wheels (very simply stated). With the Model S I would assume that the differential would be built into the gearbox, but how would they get that output to each wheel considering that the motor sits on one side of it and the power inverter on the other side of it?
Perhaps nobody here knows and that's just part of the magic of their shrink-wrapped drivetrain, but that one has been bugging me for a while.
The one thought I had was that perhaps instead of taking one input and creating two outputs it takes one input and creates one output. The wheel closest to the motor gets a more direct output from the motor and the gearbox handles differentiating it only to the other wheel while the power inverter is just kind of wrapped around that axle.
While I'm not a mechanical engineer, the design they chose fascinates me.