2005 Chrysler PT Cruiser alignment of rear wheels

We have been experiencing unusual tire wear on the rear passenger tire. The other three tires are wearing normally. But the passenger side rear is out of tow and camber even though the Chrysler dealer says it is within factory specification on all four wheels. You can visually see the tire leaning away from the car at the top. The wear pattern is all outside tread gone plus numerous scallops on the middle and inside. This tire has only been on the ground for 15,000 miles. We bought all 4 Goodyear Eagles at the same time. The first set was rotated regularly but both passenger side tires were worn in this same pattern due to rotation to the rear. I have not rotated this time because the same wear pattern showed up on the rear tire very early, within the first 4,000 miles. I still have three good tires as a result of not rotating the passenger side, so I am certain the culprit is the rear alignment, for which there is no factory adjustment! In my estimation this is a serious design flaw for which there is no simple, inexpensive fix. The shocks, struts and suspension seem to be fine but the only cure I have heard about is the trial and error installation of shims while the car is on an alignment machine, a process which costs between 250 & 350 depending upon the total labor time plus the cost of the shim kit.
I believe Chrysler should pick up the tab for this situation because they, in effect designed and assembled the car with this flaw.
Don't get me wrong, my wife and I have a lot of fun in our PT Turbo Convertible, however, if it were not so much fun to drive, I would send this one back to Mexico because in just 64,440 miles it has had to have 4 computer modules, a total replacement of the AC system, one component at a time, a cam sensor, a broken hub and it still has intermittent electrical faults and signals in spite of the hundreds of hours it has already spent in the dealer's service department. I do not think my wife and I should have to foot the bill for what is an obvious manufacturing defect. It was purchased brand new and we only have 8000 miles of extended warranty left. What should we do?