FWIW, I joined as a premium member several years ago, partially because I wanted an ad-free experience but mostly because I often sell stuff on the C&V sales forum. It was been worth every penny over the last decade or so, and PayPal has facilitated many purchases and sales of mine as well.

The C&V forum IS my top recommendation for your quest; also consider going to Google groups and joining Classic Rendezvous, Dale Brown's internet sandbox that has been going since 1998. The two groups overlap some, and you're most likely to find someone who has what you are looking for. For that matter, between the two forums, if what you are looking for isn't available in the U.S., many of these folks have direct connections to collectors in the EU.

Good luck!