Except there would be no finder's fee. There's nothing to find. It's not like we're talking about a bunch of coins in circulation. They could mint 5 of them, and put them in a box somewhere and say "We've got 5 Trillion in coins in the reserve". The important part isn't the 5 coins but the understanding that there's 5 of them minted in such a way so as to not count against the debt ceiling. Someone finding one is irrelevant. Heck. They don't even actually have to have the coins (although there might be some law requiring it, don't ask me). They could just mint them, put them in a box, and the incinerate/melt it. It's the idea that there's X number of dollars backing our currency that doesn't count against the debt ceiling that matters. The physical coin is just a necessity to get around the current debt ceiling legislation. As others have pointed out, it does not change the number of dollars actually in circulation one dime.
Having said all that, I don't think it'll fly legally. We all know it's just a loophole. The law clearly was intended to place a limit on government debt. Period. Making a coin out of a material not directly specified in the law is pretty iffy. Can I make a coin out of air and just say it's in the box? How is that different than just writing a number on a piece of paper and declaring it currency? It's an amusing speculation, but really really unlikely to be actually attempted.
Edited, Jan 7th 2013 2:21pm by gbaji