The "luxury" premium sleeve would be one made from shim steel.
I think some off the shelf items are available - maybe from Chambers Airgun Spares or John Knibbs?
However, many people have enjoyed success with home made items and they're easy to make. Materials can be PTFE sheet, drinks cans, plastic bottles etc., as you mention. Many drinks cans these days are aluminium. If you preferred steel, I think Jon Budd said that WD40 cans were steel? Generally considered harder wearing than aluminium. And many of us have been spotted trawling supermarket shelves armed with magnets in the past!