@lewm, lots of other tables have had their motors mounted on a stationary platform and their platters suspended: the Acoustic Research, Thorens 125/150/etc, Oracle, VPI HW-19, and of course the Linn Sondek itself. Did the old Sapphire have the slow-acting servo-control speed-correction that was clearly audible?
The new SOTA/Phoenix Engineering combination motor/power supply/tachometer is a dedicated, 3-phase DC motor design. Honest! SOTA is offering a version for use in VPI tables, the DC motor replacing the stock Hurst AC motor. PE’s Bill Carlin is adamant that a properly designed DC motor is far better than an AC: less noise and vibration, more torque and "drive".