After some online research I decided to use Andrews Powder Coating in Chatsworth, California. They focus on powder coating for cars and motorcycles, and they are a supplier to ICON. That's good enough for me.
The wheels came back looking like new. I had Andrews match the OEM semi-gloss black. They masked the lug bolt and brake drum bearing surfaces at no additional charge, which saved me the trouble of scraping the paint off later. Wheels can come loose if these areas are powder coated, so it's best to keep them unpainted.
One interesting thing about these wheels is that they're all factory replacements made after 1964. The newest one has a September 1970 date stamp. Three of them are safety rims with additional bumps that keep tubeless tires from breaking the bead on very hard cornering. I really like the idea that VW was still making parts specifically for the earliest VW 1500s into the 1970s, and incorporating safety improvements into them too. I still have all five of my Ghia's original April 1962 stamped wheels, but I'll keep them in storage and use these newer ones on the road.
I found a very nice used Pirelli Cinturato CN 36 tire recently, and I had it mounted on one of the newly powder coated wheels as a test. Pirelli has reissued the early '70s vintage CN 36, and I'm thinking about buying a set of them for the Ghia, but since they're slightly wider than the original size (175-15 rather than 165-15) I wanted to see if there were any fit issues. There aren't. A bit more expensive than the comparable Michelin XZX, but with an extra helping of awesomeness. My car now has a very cool spare.
