I don't know if they are available for my aftermarket MII control arms, but I intend to check. I had intended to eventually make something similar out of Delrin or Teflon to eliminate the polyurethane friction , but sometimes it's not worth the effort to make something if the price isn't too high for the commercial parts.

Those actually look to be made from Teflon. It's only available in white, as far as I know.