40mm to Leica M39 adapter?

I have a couple of 40mm to Leica M39 (STEP-DOWN) adapters -- these are hard enough to find, but allow me to put Leica M39 mount lenses on #1 shutters.

What seems even harder to find is a Leica M39 to 40mm (STEP-UP) adapter -- to allow me to put #1 shutter lenses onto Leica M39 cameras and devices.

Anyone ever hear of such a beast -- or is this another Frank Zappa situation?

An M40x0.75 to M39x1 adapter I think is what you're looking for? You'll have to figure out focusing via a helical or extension tubes, too...
RafCamera and Custom Photo Tools both make many unusual thread adapters as well as doing custom work. I've been satisfied with adapters from both companies.

That's what I'm looking for. I've dealt with RAF in the past -- and I should have thought of them. They do make a lot of "unusual" adapters -- I have several.