The business with the round buttons draws my attention.

On of the things I like about my Mk2a is the fact that it's very easy to find the right button in the dark because Up is a distinctive shape (convex, unlike the other buttons). I'd hate for you (or anyone) to lose that kind of help on a custom facia.

It doesn't have to be the shape of the button itself, of course. Some kind of guide on the actual face could be equally good.