I was thinking this, too, though I was thinking more just "heck with it; wear mismatched earrings". It'd go better with some outfits than others; I think the key would be making it look deliberate - formal/strait-laced clothing would make it look accidental, while (depending on the specific earrings) I think it could work well with more artsy/eclectic wear. (Esp. since: how often does anyone look at both of your earrings at the same time?)

Other notions: Necklace charm(s), memory-book, take digital photos of 'em as keepsakes to replace the actual items, hair-charms? (would need to be mounted on something appropriate)

Less serious notions: Wine-glass charms, fly-fishing lures, weld them together to make little sculptures