How about having someone custom-design one for you? I recently had a guy from Grand Traverse Boatworks try to sell me on a custom design for $150. Eric Schade might do it, but I don't know what the fee would be. If you want something that's more than just a racer but more of a fast cruiser/day tripper, I'd try some variation of the East Greenland style kayak -- check Sea Kayaker a few months ago for an article on these boats. They had more flair to the hull's side panels than the West Greenland boats, and a very narrow waterline beam. This makes for a fast boat with low initial stability. Given the flair, though, you would still have good secondary.

Dean