The trampoline system you are describing went out of fashion a long time ago in the Tornado class. You can either build one yourself (quite an easy project) or have a sailmaker do it. I dont think you will find a usable one on the used market.
Why dont you want a more modern trampoline?

For the mast, clean it, check all fittings and replace bad fittings/rivets/wire, then go out and sail the boat.