However, part of the Evaluation Criteria is that it "be equipment that avoids unnecessary or excessive costs." How is the committee supposed to evaluate that if a price hasn't even been established for the boat?

Nacra isn't without a business plan, I fully expect that they do have some idea about how much the boat will cost to produce. Chances are that, if they are being cagey about how much the boat will cost retail, it is because they have two different prices in mind depending on whether or not the committee chooses the boat.