Interesting question. As MikeK suggested you might have the RD bearing worn, but see first if you can feel any play at the wheel?
A few tests might turn up something. The were some reports a while back of people replacing rotors with oem and getting runout. You could first check your new rotor on a surface plate or plate glass with some blue to make sure it's not warped.
Have you first checked what your ABS rotor to sensor clearance is doing? Measure with feelers at 3 equidistant points of wheel rotation bike on and off center stand. Compare results.
It's not guaranteed to work but here's a couple of ideas: First mark on the rotor where max runout occurs. Then check at the wheel rim, remove wheel and rotate a stud at a time. If the wheel is true (unlikely) your 20 thou comes out as 30 thou at the rim. As you move the wheel around, If the position of max runout on the rim moves, then that suggests it's an error in the rim to be ignored. If however max runout stays at the same position, relative to the frame, then that suggests the axle bearing. You could take this a step further by rotating the rotor to different positions to- changing max runout position likely to be the rotor or it's not seating properly on the flange. It's easy to get some dirt behind.
I tried measuring runout on my front rotors. It's not that easy, particularly as the front rotors have holes in them. The real test is also if you feel it during braking?
If you remove the ABS ring and rotor you can get a dial gauge on the face or edge of the mounting hub just forward of the seal without dismantling further. Fit a temporary long piece of flat steel with a couple of holes picking up 2 wheel studs. Heave on the bar whilst watching the dial gauge. If you get big changes look at bearings. If there is a fixed runout that doesn't change position when you heave - that's real bad news.
Your dealer won't be diving in there with dial gauges - they probably felt pulsating braking on the rear. If you guys have brake test machines, they can tell this by slowly applying a brake and watching for the fluctuations in braking measured on their roller wheel. Make sure you have a set of decent pads in there and check ALL pistons are free and move easily. They can seize or stick on older bikes.
Never pay again for live sex! | Hot girls doing naughty stuff for free! | Chat for free!