I can mention it to the casters and machine shops that I've been speaking too. Should be simple to plaster cast. But I wonder if the metal buttons are machined, maybe they could fill the space within the U-shape of the handle, thus reducing waste. 10 buttons in the space of one handle U-shape might be a good use of metal.

[Edit: added]
Or, a long U-shaped metal extrusion could be created. It could be sliced into many handle shapes, each milled to perfection. I'll also run this idea by the metal shops.

I just need a CAD file for the handle. My trusty plastic grade school ruler might be a little less than accurate to create the CAD by hand.