Many enlarging lenses are 39 mm thread mount. That is same as leica thread mount, so adapters are plentiful. For focusing i have purchased 65 mm diameter helicoids on Ebay. Depending on extension and seller-$25-$45. Front plate is 39 mm female to 65 mm male to mount lens to helicoid. Back plate is 65 mm female to 39 mm male. That goes to a 39 mm to Sony adapter. 65 mm adapter are direct fit on Leica bellows, too.

You can get blank 65 mm plates and drill your own holes for custom sizes, and there are many predrilled sizes, such as for large format lenses or 42 mm thread.

I originally got into the 65 mm adapter system for easy mounting of view camera lenses with leaf shutters for flash work. If you drill a mounting hole off center, by rotating the mounting disk you can obtain lens shifts for perspective control.

Your best option is a mirrorless digital body. With the removal of the mirror, the flange distance of mirrorless bodies are much less. Flange distance - the distance in millimeters from the lens mount to the sensor / film. Now, most any legacy SRL lens can be adapted to most any MILC with a simple metal 'donut' that holds the lens at the proper longer distance of the legacy lens mount. MILC - Mirrorless Interchangeable Lens Camera. Any MILC brand will work. You just need an adapter that addresses the old lens to the new target mount.