The keyboard market makes me wonder if there would be a market for custom pcbs in customs shapes instead of just flat, or possible a 3D printer that can deposit both a polymer and conductive traces.
Non-flat PCBs would be a massive hassle to solder components to; normal pick-and-place+reflow is out of the question as the components would fall off, so you'd have to resort to gluing them on or soldering one leg manually.
Flexible (polyamide) PCBs are already available, with FR4 stiffeners where components are to be soldered. You could assemble one flat, bend to desired shape and attach to a form.
