One day in June, Scott Amron came home and tossed his keys on the kitchen table. Then he paused, eyeing his pocket-jinglers, and had a Hudsucker-ish inspiration: Why not combine the key and the key ring? Amron makes a living turning far-out concepts into workable prototypes for outfits like Oxo and Polder Home Tools, so he rendered a design and posted it on his Web site, amronexperimentalWithin a day the sound of head-slapping had reverberated across the Net. Within a week he was in touch with a manufacturer. Within a month he had more than 25,000 preorders for his key-plus-ring, which can be cut to fit almost any front door in the US. Only one problem: The design he posted used his own front-door key as a model; a resourceful thief would have no trouble making a house call. “I had to change my locks,” Amron says. Small price to pay for an idea everyone wishes they had thought of first.