Interesting topic, I am going to continue to buy the non certified silver but if anyone is looking for a future business then something along the lines of slabbing coins might be worth looking into.
A third party certification company who will check the precious metal, confirm that it is genuine and then encase it in a tamper proof slab. Someone with the money to make sure that it is hard to countefeit the packaging, someone with a decent reputation who people would trust. It might work out to be cheaper that a certificate and less likely to be lost. I usually end up keeping the metal in a safe and the certificates and boxes on a shelf somewhere else.
Actually, is it too late to copyright that idea?