Reminded by @ddrfraser1’s HHKB+numpad post here, and recognizing that most keyboards don’t have passthrough these days, I wonder if anyone has added a daughterboard to their keyboard (and presumably added a hole in the case for the port) to add this capability? Seems like it might be useful to attach a mouse or numpad to an otherwise solo board.
Might not be what you had in mind, but there is hub16 and hub20. Which are macro pads that have multiple USB-C ports to act as a usb hub. You could plug your keyboard into the numpad, rather than plug the numpad into the keyboard…
I probably wouldn’t mind if the modification was done on the back since you don’t see it when typing…but on the top left…man…looks like a nice keyboard too.
EDIT: I saw this video a couple months back where a guy put an entire computer in a Model M: https://www.youtube.com/watch?v=d6TgVDCAcN0 USB ports included