So as part of the repairs on the Rossion, we are also doing some upgrades. We have decided to add some camber adjustment to the upper control arms in both the front and the rear. You can see one of the rear arms with the modification completed in the picture below in the jig that was made to make sure as things were welded up/modified they were centered around the original factory dimensions - the other welded tabs and holes on the jig are for the fronts.
While I know this only has one degree of freedom and is not the equivalent of a full on race arm that can be adjusted by an inch or so in or out independently on each arm it is a very pragmatic solution that doesn't require complete reconstruction of the control arm from scratch. Before anybody talks about binding due to lack of degrees of freedom I can assure you that the off-axis tilt induced by up to a degree of change in camber is less than the tolerance of the parts from the manufacturer - which are actually not as tight as one might think/prefer Also, we have tested them out and they work to do exactly what we wanted. Anyway, just another option for those of you looking to get some degree of adjustment to make up for manufacturer or wear tolerances.