I would love to have customizable PBT caps because I use Colemak rather than Qwerty, so at the moment the only option for me is to buy blank PBT keycaps, but I like having the print on them for number row usage, for when I want to type a few words using one hand (while the others is used for eating at the computer lol) and just aesthetically I think printed keys look nicer than blank ones. Not sure how useful I'd be at finding a manufacturer though I guess I could poke around on the Internet randomly, don't really know where to start.