You and I share some things in common. We are both looking for equipment which is uncommon, expensive, heavy and bulky, and used by a small number of people engaged in a unique activity.
Passagemaking "gear" does come up if you are patient. People do buy boats which have this gear and strip it off and sell it. If you are patient and diligent you will find your gear. You have one benefit over me which is that being Belgian you can easily search in French ... and the French are great long distance sailors. Do your google searches also in French, and be patient. It took me a year to find my hydrovane, six months for my diesel burner, I'm still looking for some barbarossa winches (but I found some on Marktplaats last week, which it seems I just missed!) ... be patient!