Gord, I think I'd get more than 28 feet...
Cost is largely determined by length. But it's even more determined by displacement, and also by systems, construction technique, and finish. Even if I were looking to build my fantasy 36-footer, it still would be a boat that would displaces no more than 5 tons, that sleeps at most five, that has one, manual head, that has its first five feet dedicated to a collision compartment and storage, that has it aft eight feet dedicated to cockpit and lockers, that doesn't try for standing headroom forward of the mast, that has no generator, no power winches, no power windlass, no bow thruster, and no AC, that has very little exterior brightwork, that shows simply the unfinished, inner part of the hull on most interior surfaces (something that I think looks quite fine on a cold-molded hull, but that a lot of people would view as "rough"), that has at most two cabins, that has no more than 12' of beam, and that sails circles around most production 40 footers. Yachts get expensive partly because people want them fat, stuffed with the interior of a modern condominium, and full of push-button, powered systems. Both low-end and high-end builders aim for those long checklists, though in different ways. People would get more boat and better quality for a less money if they went for good design done simply and straightforwardly. But there's a precious small market for that.