The 1.25 C row 'caps lock' position key is the most difficult. 1.75 Enter with legend would also be very hard to acquire. They do both exist from Cherry, but only on some very early 1980's made models. Using a 1.75 blank caps lock for enter from an imsto set or something would be easiest. Everything else should be easy to get. It's pretty obvious they didn't take consideration to Cherry/GMK/etc key when they designed that boards key sizes.
If I had one, I would probably grab an ISO 1800/7000 model to get the most correct key sizes at once, then add some 1.25 mods from something else and the blank 1.75 return to make life easier.
