Blue Moon Camera (Portland, OR) confirmed by email a while back that they can work on a Contax II -- not sure if that transfers to an RX, but they're an advertiser here, so it shouldn't be hard to find a contact link.
+1. I've bought a couple of cameras from Blue Moon (Bronica ETRS maybe eight years ago and a Nikon F2 3 or 4 years back) both CLA'ed or refurbished, both in excellent working condition and still working perfectly.