You could try putting up a "want ad" in the classifieds here, probably as good a shot as any. Otherwise you'll just be looking on eBay, marketplace, craigslist etc.
Keep in mind that you might not get good usable rims that way either, they're pretty old at this point so you could easily get bent rims. The cop rims I ran on my Duster were original, and one of them in particular was pretty out of whack. And those are pretty heavy rims to begin with. But guys are definitely upgrading from the 14" wheels because of tire availability, so I would think you could find some out there.
