[masmole]

If I'm not mistaken the comfort plus mode on the 7-series sedan is based on the following as detailed on an article I found on autoblog:
"a complex system called Active Comfort Drive with Road Preview adds anticipatory functions to the active chassis with air suspension, while the Integral Active Steering (variable-ratio rear-wheel steering) now comes with all-wheel drive. The automatic transmission downshifts on its own, based on what the navigation system tells the transmission about the road ahead, for example a hill"

What seems like the equivalent of this system is optional on the X7 via the $4750 Dynamic Handling package. Details on the X7 configurator describe this system as:

Active Comfort Drive with Road Preview

Active Comfort Drive's electromechanically-operated stabilization system allows your vehicle to handle corners with comfort and precision. Road Preview uses a forward-facing camera mounted behind the rear view mirror to read the road surface and adjust the suspension system in real time via the Dynamic Damper Control system. Together, they impart an unrivaled combination of sporty handling and luxurious riding comfort.

Integral Active Steering

Integral Active Steering maximizes agility at low speeds and maximizes stability at high speeds. At lower speeds, the rear wheels turn oppositely to the front wheels, allowing for a sharper turning radius thereby making parking and cornering easier. At higher speeds, the rear wheels turn in the same direction as the front wheels, which helps improve vehicle stability and lane change comfort.

Probably not as sophisticated as the comfort plus mode of the 7-series but I'm sure it's not far off if not nearly equivalent in effectiveness. To me the ride quality in X7 is equally as superb as the 7-series. If anything, the 7-series just benefits slightly more from plusher rear seats.