I checked the rotors with a dial runout gauge. The rears are only 2/1000ths of an inch from perfect (within spec). Also if I try to stop using the parking brake (rears only) there is no judder. The fronts measured true with no warping at all. Could the problem be in the suspension or steering rack??
A dial gauge tells you how much the rotor is 'wobbling' from true, but does not tell you thickness variation? OK, you could measure both sides, but now you need to match up the highs and lows on each side, which can be done, but is getting tricky, given the available space.
Can you check the rotor thickness?
Did you check the runout of both sides of all four rotors?
Have you checked that there is no corrosion between the hubs and the rotors and between the rotors and the wheels?
Was the rotor clamped hard to the hub while you were measuring it? (At least 3 lug nuts, maybe all five for a precise measurement)
Does it improve or get worse with heavier braking?
I'll stand corrected, but being 'within spec' does not mean zero judder when braking, it means 'an acceptable level of judder'.