The uppers were always the worst. They're part of the arm and not serviceable. There were a couple people over at SM trying to figure out way's around this. One person have the stock arms machined and a sleeve added so that they could have a smaller but less expensive and easy to find ball joint pressed in; The other had custom tubular arms built which would accept a comparable size ball joint. I don't remember anything more than that.
A quick search shows that O'Reilly has an OE control arm with ball joint for $125 per side:
http://www.oreillyauto.com/site/c/de...0317&ppt=C0106