BikeCad does a reasonable job of designing a frame given a set of measurements. Then it will show you the rider on the frame it designed. Of course, there are a lot of fit calculators out there. This isn't quite the same thing as fitting a rider to a stock frame, but it's not that hard to back out the info you want.
Originally Posted by
safariofthemind
A mechanical engineer acquaintance explained that bike frames need to be analyzed using finite element analysis and that it is not trivial.
I don't see any reason to do this other than for a fully optimized carbon frame that is made to be as light as possible. People do not understand what makes a bike that feels right to most people. If there ever was a touring bike that was designed using finite element, it was for marketing purposes.