That is some remarkable stuff. I remember being fanatical enough in the 80's to slightly modify the keyboard matrix of a Tandy Model 4P keyboard so I could install it in a Coco3.
You do clean work.
I was thinking of something similar myself, but going the easy route with a keyrah adapter. Then either a Mac Mini or a Powermac motherboard.
After all, since no PPC adapters fit an a500, I don't think MorphOS has ever been run on one.