Been playing the Ruger game for close to 3 decades and this is the first I'd heard of such a thing. A single cylinder requiring the changing of barrels seems very unlikely and awkward for when it's actually needed. Additionally, what happens when the the person forgets to change the barrel and fire a .22 in the .357 cal bbl or vise versa? Change the barrel every other shot? Yeah, REALLY don't think so.
I have seen .22 chamber inserts made to shoot .22 in a larger caliber revolver. I saw a .455 Webley converted as such yesterday. Much like inserts to shoot 20 or 410 gauge shotgun shells in a 12 gauge.
People try all sorts of things, but I can't imagine anything like that coming out of the Ruger factory, and I would not recommend it.