Good question, I have not seen anything worth building, I mean the nicer ones, best lines, engines lift and all, you might as well buy someone elses design. I think I would prefer to use the best as far as engine and controls but changes the over all appearance. I do not have the time or know how as most have said to do from scratch.
I would not buy a kit, right parts, right help, copter pilots I have known for years but desing my own yes. I woudl be man enough to say I am over my head but then again why build something easy?