What is your goal with the project? Are you just making a one-off for yourself, or do you plan to get the community involved and perhaps sell a few units?
If you are just making a one-off design for yourself, that you don't really think will have much broader appeal beyond existing designs, then the most logical way to undertake the project is to design a plate, have it cut or machined, and hand wire the switches. That was my purpose in creating this thread:
Prototyping New Keyboard Designs (Using Plate Mounting and Direct Wiring).
I recommend using 1.5mm (0.062") thickness steel for your plate, and (if hand wiring the matrix) making the holes stock Cherry spec squares, that is to say no notches for switch-top opening).
Lastly, what is your goal with regard to layout? Are you familiar with my JD40 and
JD45 designs? I am guessing that they are not suitable for your purposes, for whatever reason.