If you are involved in selling custom or replacement keycaps, for the love of Puffy have the ability to search your options by whether "shine through" or transparency is supported, and whether that support is for south or north facing LEDs.
I may actually do that. I had to order through Amazon because the vendor (YMDK) that I ended up with didn't have the ability to search by backlight, or backlight type.
Just being able to search by accessibility features alone would be worth doing it.
Also, having say, additional options for side print vs top print:
EMACs/VIM keybindings on the side, letters on the top, or the other way around.