I wasn't thinking of designing the perfect bike but showing how basic frames fit basic dimensions. Just about every manufacturer gives you a geometry chart and if you combine that with inseam,torso,forearm, reach, thigh, lower leg, sternal notch and height it may give a good indication of the best frame size without the fine tuning. What made be think of it is this thread (below). It is hard to figure somethings but a model might reveal what is wrong. I think in my case my hands prop me up like legs on a stool, with no bend. Most people on that thread think my bike is too big but the seat is almost as high as I can get it and I haven't got a lot of spare stand over. What I'm saying is a simple model may show the dynamics of your particular body type (long torso short arms/short torso long arms etc).
http://www.bikeforums.net/showthread...0#post11918930