In principle SP should be able to manufacture something like an SA key with a Model M underside, in much the same way that Unicomp's current replacement keys are one piece. SA can mold a number of key switch interfaces including Cherry MX and "square" so I assume blank is an option.
An SA row 2 thin key (like the red Esc that I just ordered from SP) may even be *just barely* big enough to fit atop the bottom half of a regular old Model M key.
Yes, I too was thinking that a Model M with all row 2 or row 3 SAs would be neat.
Why do Cherry MX switch keyboards need to be flat? Something like the Kinesis Advantage shows that switches can be put anywhere.
I've been thinking of a board design that has say 6 different PCBs, one for each row, with each PCB mounted along a curve. Then, SA group buys would be "easy" (just one profile!). Colemak and Dvorak and Workman and whatever users could just move keycaps as they see fit. This would just use PCB mounted switches.
SA keycaps are still not PBT, though. I wonder why. I wonder if the spherical shape has something to do with it. Can anyone vet this argument on
https://en.wikipedia.org/wiki/Computer_keyboard ?
"Initially, sublimation printing, where a special ink is printed onto the keycap surface and the application of heat causes the ink molecules to penetrate and commingle with the plastic modules, had a problem because finger oils caused the molecules to disperse, but then a necessarily very hard clear coating was applied to prevent this. Coincident with sublimation printing, which was first used in high volume by IBM on their keyboards, was the introduction by IBM of single-curved-dish keycaps to facilitate quality printing of key legends by having a consistently curved surface instead of a dish."
This argues that spherical keycaps + sublimation printing = no good.