The Apple keyboards of this generation (M0116, M0118, AEK and AEKII) have the key-switch assembly mounted very low in the case, and there are dimples in the bottom of the plastic case for where the bottom row's switch pins go. To fit, the switches must be mounted on these specific locations with the switch pins north.
This means that for a modder to fit Cherry MX switches on the bottom row, he would first have to grind away some plastic with a Dremel to be able fit the centre shafts.
It would be hard to find 1.75u modifiers for Cherry MX mount (unless you use blank or a non-contoured profile like DSA), and the space bars of 4.75 and 5.25 are
nonexistent.
Cherry MX does also not have any equivalent to the M0118's super-narrow Return key.
An equivalent to the M0116's 1.75×2 backwards-L key
does exist however, and it has the switch in the same position.
No, I won’t be offering MX plates. I used the footprint to give people the option if they wanted to go through the trouble.
BTW. A plate that would fit Cherry MX would also fit SMK Alps-mount and Mitsumi Alps-mount.
Clicky SMK Alps-mount are
very nicely clicky in my opinion, but a little scratchier than Alps on off-centre key presses. I have not tried Mitsumi Alps-mount, but the tactile Mitsumi-mount are really nice: more stable and tactile than any Cherry MX ... and also much rarer.
Supporting three or four on a single position would require at least one switch to be upside-down though. Alps needs to have pins north on the bottom row and Cherry MX would need to have pins north on the home row and lower to support QMX clips.
How about leaving fitness into the Apple Standard Keyboard aside for a moment and consider a
generic PCB that would also support a
15u alphanumeric section + numpad.
Then
that could be a reason for supporting Cherry MX, and could perhaps also be a way to get the order quantity up.
Most keys would be the same, but for the bottom row, you could offer more options:
The two top rows in the figure are the bottom rows for the keyboards already supported: M0116 and M0118
The others are bottom rows for common layouts: a green key already has a switch position, and a red key would have a position unique for that layout alternative.
Fitting normal-sized right Shift, ANSI-\, Backspace, and ANSI and ISO Return keys is easier...
However, there are two types of regular-sized Alps ISO Return keycaps out there: switch centred in the 1.25×2 rectangle (Matias ...), and switch centred in the 1.5×2 rectangle (Dell AT101).
(BTW. Support for the latter would also allow replacing the M0118's super-narrow Return key with one from a ISO AEK/AEKII. Some mod to the plate and case also required of course)