While the concept of proportionally sized components is not new, and is currently done to a small extent, the lack of all aspects of bikes doing so is challenged by basic economics. The cost to get to market, a range of component sizes in otherwise similar grade/levels, has to be supported by the consumer spending the $, and doing so for long enough to establish this as the "way to do it".


An excelent example is the Terry bicycle. A solution for many smaller riders but never became large enough to sustain bikes as a stand alone. Early on many main line brands did their copies of the Boston/Terry design (some even without shortening their top tubes!) but soon learned that the market wasn't there to support all the added effort to bring their terryocki bikes into your LBS. (And some of this is also shared by the LBS staff and their often lack of enthusiasm). Soon the big brands turned to a dual 650c design as their sole offer to short riders, and again soon enough they pretty much all don't any longer.


So where the market will support it proportional sizing is already done (shoes, cranks, stems...). New aspects of sizing may or might not popular depending on people like the OP to step up and fund the trial. Andy.