Actually, I think Calfee does Serotta one better and addresses this very need.
The
Calfee Fit Bike "
can quickly and easily adjust all the important dimensions with quick releases and a hand crank top tube extender. The top tube extender is especially handy for the rider to feel the effect of a longer or shorter top tube while the technician turns the crank handle. You can duplicate the geometry of any manufacturer's production frame directly from their published geometry charts. This allows the rider to test ride a demo bike that may not fit perfectly just to get an idea of the ride quality. Then they can check the fit of the correct size frame and get the right stem length and saddle position on the first try. This makes special ordering frames easy and risk-free. "