I assume that, for the purposes of this analogy, there is no gold in the economy already and nobody recognizes it as valuable based on past utility... all recognized value would be speculative, based on predictions of future utility?
I also note that in scenario 4, the buyer doesn't corner the market, he merely puts himself in the shoes of the seller: he's got tons of worthless coins that he has to figure out how to make valuable.
What you do is stamp the gold into coins with pictures of all the Presidents, so people want to start collecting them. The thing is, you make sure there are more coins of some presidents than others. That way you create a shortage for some collectors.