Plating is not good as the plate (esp. these days is usually too thin).
Really, only way, is to do it on a rough hewn part, i.e. cut metal, not cast/plated.
It is a shame as am sure would be a market for it. That being said with the proliferation of parts for guitars and the demand am sure the extra cost seem's unreasonable to manufacturers.
Need a classy forward thinking guy like Tim to start making more 'custom' finished parts.