You had me at polycarb + brass.
Seriously this is an superb design but I will say this again. I don't want any more 60%. Make it 66% at least, 70% or better still give us a full size in this design with ISO included. There are enough 60% around.
If you were to make it 100% or even 100% - FKeys it would look very like the keyboard of the 1980 Memotech 512 computers. You could have a black and red plates.
I agree, bigger than 60 would be nice, but on the other hand one of the reasons the format is so popular is that it’s easy to design a tray mount case. Most 60s use the same mounting points based on the Poker, and so it’s easy for beginners to build a board and just upgrade the case, and you don’t need to design a custom PCB etc.