junior spindle
It seems odd that you have so many varieties of the same size PCB. It's pretty common now just to have one PCB but it supports multiple layouts, whilst it's not as common on HE PCBs brands like Rakka have already done it and proved it's possible. Yes each PCB would be slightly more expensive but it'd overall save on only having to stock one PCB per layout, cheaper manufacturing, warehouse storage and probably more. You could easily fit ANSI, ISO and JIS onto one layout. If you really wanted to appeal to the custom mechanical community add popular layouts like stepped caps, 7u spacebar and split spacebar/shifts/backspace where applicable.
hollow tree
glass igloo