In Dan logic terms, I was not about to fiddle with plugging/unplugging cables, or with flashing/reflashing controller firmware when switching between CNC controllers, so that created a need and a perfect opportunity to design a dual-controller switcher box! Nameplates were a fringe benefit/bonus!
Truth be told, I took on this project because of @Jorge as he threw down the gauntlet and said "I must share"... needless to say I did not think it was going to be a 6 month process... It's all about the journey and I acquired a lot of usable proficiencies. No complaints here other than "what took so long"?
Thanks everyone for the kudos...