It is pretty impressive what you can do with "silk screen" printing on PCBs these days. I think JLC even offer full colour now (not tried it). I imagine they have a UV printer.
But for some of my smaller run boards, doing an over print of the assembled PCB could be very useful.
I already have code to make 3D cases from PCB files - I can see me automating making an SVG overprint from the files.
