Your right, 22 jet cylinders in 22lr are hard to come by. A good machinist should be able to chuck it up and shave the face a tiny bit no problem though. 3 thin pieces of brass or copper, held to the cylinder with drop of super glue each will protect the cylinders finish. The face of course will lose its finish, but some good cold blue and a few hundred rounds with minimal scrubbing on the cylinder face should pretty much fix that.

I keep think of making a 53 22lr cylinder by lining the chambers on a model 19 cylinder and using a K 22 extractor. Not very high on my list because I already have a selection of K22s.