Hey Mitch I don't know where your located, but there is a place down in Monroe, NC, not to far from us, called Iron Peddlers. They carrie alot of used and aftermarket CAT parts, and if they don't have what you need they can usually find it for you. I'll attach a link in case you want to try them. There is also a place in SC called Spartan filtration that should be able to make you one,alot cheaper that CAT, at least in our past experiences with their work. I don't have their number with me, and I've never been to their shop, they've always picked our stuff up, but I believe they are in Spartanburg, or one of the little communities near there.
Good luck finding your cylinder.