Finished Clutch / IMS Job, now have scary mystery squealing noise

[black_box]

I was planning to return home tonight and write up my IMS experience for posterity. Instead, I find myself pondering a worrisome noise that started as soon as I fired the Boxster up after the job.

To set the stage:

I just replaced the clutch w/ sachs kit, pilot bearing, throwout bearing, clutch release lever, installed a low mile resurfaced second hand flywheel out of a wreck, replaced IMSB with Pelican / OEM type replacement bearing, bolted everything back up and torqued it all down.

The noise is a high pitched squeal, sort of like a bad wheel bearing or belt. It only seems to happen under engine loading, but does not depend on clutch position or gear.

I noticed it immediately when pulling out of the garage, giving partial throttle. When driving, the noise is only present when accelerating -- it goes away when I back off the throttle.

I can also make the noise when not moving in two ways:

Firstly, with shifter in neutral and giving it throttle, the noise is present while engine speed increases, but not when it is constant or falling.

In gear, when I slip the clutch at idle against the brakes by using two feet I can produce a constant squeal. I did this while the car was on a lift while an associate poked around underneath. He seemed to think it was coming from the driver's side axle area.

Some thoughts:

It shouldn't be the IMS bearing (god help me if it is!) or serpentine belt because they shouldn't care about load, only engine RPM or rotational acceleration. It shouldn't be the clutch, CV axle, or wheel bearing because I can make the noise while stationary in neutral (by poking the throttle). It shouldn't be the motor/trans mounts or dual masses of the flywheel because of the continuous nature of the sound, which means it has to be something making full rotations.

I am stumped, and scared. Please give any constructive input. I will try to make a recording tomorrow and will not be driving the car until this is solved. Thanks.