Providing it is associated with steering wheel movement-Try driving the vehicle with the right side carpeting removed. If the noise gets louder with the carpet out I would be thinking "Idler Arm" bushings.

If it is a rotational type noise related to left turns only then perhaps you have an unusual bearing noise that simply changes pitch due to load changes on the bearings. You may want to double check your rear wheel bearings for excess play, I had one of those and it was real deceptive.