My thoughts...if it were a wheel brg. youd've heard it by now, shocks won't cause a steering wheel vibration [actual cyclic radial oscillations] AND you say there's no vib. while braking which rules out a bent bearing hub flange for the most part....your first repairs caused a change, wasit an improvement?? HOw carefully were the inner and right outer ball joints checked and as 'Skycity BMW' said what is the condition of the arm bushings, these won't usually "cause" a vibration but will wear because of one.
Stay in touch........................jeff b.