What's the point of this? Most of us here on HN probably already own good to god tier mechanical keyboards. If I really wanted a Pi (I don't), I would get a VESA mount for it. But you have to keep it mind that Pi's can't even play 4k videos at 60fps reliably and are kind of a terrible choice for general desktop use against N100 (or later) mini-PCs, or even used thin clients like ThinkCenters with laptop CPUs that are far more capable.
Maybe it can be an advanced keyboard that does more than just a keyboard. Like maybe it calls an LLM and types shit for you, and you plug it into something else as a USB device, and implement USB 1.0 by bit-banging the GPIO or some shit
I don't own a mechanical keyboard but it's fun because you could upcycle it at end of life to a cool keyboard.