I hate to rain on everyones parade, but asking price and selling price are to entirely different things. You might ask $30,000 but getting it is a bit tougher than that.
Most, if not all of the Bullitt's that were/are listed on Ebay, have not even met their respective reserves.
Bottom line is the cars are only worth what the market will support, and as of yet I've not seen them actually selling at those inflated prices.
Even cars more exclusive than the Bullitt don't escalate in value after the initial sale.
Perhaps with time they might gain value, but with Ford's plan to produce re-makes of the Mach and the Boss, that exlusiveness becomes even more diluted.