There used to be a place in eastern Washington that did exactly this-you sent them your 20" FR5 widowmakers, and they cut the centers out and welded them into 22.5" rims so you had modern wheels that kept the original look. If they were still in business I'd do this with my old 20" rims, however as far as I know they aren't, so I just bought new 22.5" wheels. They're a little bit dorky looking, but take modern radial rubber and also won't randomly explode and kill me while I'm working on the rig :-)
