'Had 2 rears replaced on the '09 SERG, same symptoms as yours. Everything (alignment, balance, etc...) was checked several times, all within spec, I always keep the tire pressure spot on. 'Don't know how the Dealers (had one replaced on the West Coast) handled it, but the tires were replaced, no charge to me.
Last October I ran across some Vehicle Dynamics Engineers, in a Steakhouse in Kingman, AZ (Chrysler & HD share the same Proving Grounds about 30 mins South of Kingman), showed them the bike and explained the issue, after some deliberation (they bought us a few more beers

) they suggested "Shore (firm)up the left (drive) side bushings." Have since installed the GlidePro bushings, but haven't had a chance to put some miles on the bike, and see if the GlidePros have made any difference with the scalloping issue.
One school of thought on the scalloping issue is that Dunlop doesn't have the transition area on the Dual Compound tires figured out yet?
I don't think that I'm the only one that wants an alternative to the Harley Dunlops?