The price increase in Ford GT500's is not a function of supply and demand or a free market. It's the result of two economic factors working together; the price elasticity of demand (specifically an inelastic demand curve) and the realization that the GT500 can be classified as a Veblen-good.
Supply and demand is only applicable to common shared goods which are in wide demand. The GT500 is a luxury good (IE a Veblen-good) and does not fall within this definition. For example, supply and demand has nothing to do with the pricing structure for a $2.5 million dollar yacht.
While it's true that Ford controls both the amount of production (the total number of vehicles produced in any given period) as well as the number of vehicles alloted to any specific dealership, this does not in an of itself create an artificial scarcity of the item. All products are produced in limited supply and it is the manufacturer's job to match production rates with consumption (consumption and demand are different).
The price isn't being increased because of greed (greed is both a given and a requirement in a transaction when you're talking about a luxury item), or availability. It's up because the dealerships realize that they can increase the price without reducing the demand for the item (IE it's inelastic - no matter how high or low the price goes the same number of people will want it).
In the beginning stages demand for a Veblen-good is fixed and only increases due to the bandwagon effect. As more people buy the product demand will increase in direct proportion to the perceived exclusivity of the product in question (although these two ideas seem counter to each other). So, over the next six to twelve months you'll slowly see more GT500's hitting dealer showrooms, and yet the price probably wont come down significantly.
If a Ford dealership increased the price of say a red V6 Mustang 100% no one would buy it. Why? Because although it's a high demand item, it's not preceived as a must-have item (something you can't live without) or an exclusive item. Buyers would simply switch to another car.
People will pay the higher price for the GT500 because it's perceived to be an exclusive item that's worth the price.
mark h
PS - Despite what some think the US operates as a free market. You can argue that Federal and State sales tax impinges on a free market, but that argument has been run over too many times to count. The government itself does not control, or restrict the production, sale or procing of the GT500. However, there are several staple type products (such as milk and sugar) which are artifically price controlled. These items could be considered to exist outside of the free market.