rearend whine?

It's not a pinion angle thing.

If the noise is definitely coming from the rear then you might want to suspect the limited slip differential itself. When you're turning is when the diff is slipping. THe noise may be coming from that although usually differentials chatter, not "whine." It may be as simple as replacing the oil and adding a bottle of friction modifier.

If the noise is only present on left or right turns (but not the other) you may have a bearing issue. If you're absolutely sure it's not a front wheel making the noise you may have a carrier bearing (which takes the side-loads from the rear axles) but this is pretty unlikely.

If your car really is making noise only when cornering then I'll say it's not the driveshaft.

Are you hearing anything in a straight line when on the gas or off the gas?