A seller on ebay has a Nintendo World Championships Gray up for auction (number 132 for those who like to keep track). Bidding is at $255 right now so it is still a bargain.
Expect bidding to close around $4,000-5,000, which is the usual price for these over the last few years.
The seller only has three feedback but they are all positive. If you win this, be sure to pay with an escrow service just in case.