Yeah, the bottom? part of the case acts as the "plate" on the HHKB, right? A custom case is unlikely to pull that off (for any reasonable amount of money, at least).
Yes, I think that is correct. It has been pointed out to me that the Topre switches in the HHKB Pro 2 are case-mounted. I have not tried taking the HHKB Pro 2 apart to see just how the mounting is done and if it might be possible to separate the switch-mounting part of the case from the rest of the case.
Yeah, I also confirmed that the switches in the HHKB2 are mounted to the top case itself.
My mistake to think it was as modular like a RF KB, however it can still be done.
So to do a custom for HHKB2 (which would also change the user experience) would require three components:
Component 1 - custom case with metal switch mounting plate (like the Realforce) - $XXX
Component 2 - PCB from the HHKB ~ $260
Component 3 - Topre switches from a donor Realforce KB (or any other keyboard that has removable Topre switches) ~ $220
The user experience would change due to the move from plastic mounted to metal plate mounted, so no more thock.
Also the price for an individual to compile the parts for one KB is high, if a small group decide to purchase a few donor KBs to share switches then that would lower the cost. Though I think there will be other users interested in buying unused parts of the HHKBs to keep their own HHKBs looking pristine.