Have you thought about building your own hinges? I just bought some plans off of ebay, from "rod plans by chris hicks" or some company like that, and they'll send you CAD diagrams and measurements and how to make your own hidden hinges. I bought the plans to make suicide door hinges, but they're the same hinges that you'd use for hidden hinges, and the plans were only like 10 bucks. Just go to ebay and type in "hidden door hinge plans" and this guy's plans will come up. You make two hinges and put them on the inside of the door Jamb, and you have to recess two 3/8" bars into the INSIDE of the door. I don't know how the curvature is on the inside of your door, but if it's only the outer door skin that's curved, and the inside is pretty flat, these should work. I hope I answered what you were asking, but, pm me with any questions, I'll try to help if I can.