Pete Foley worked on something similar while at Apple. See "Other Projects" at https://web.archive.org/web/20190102164746/http://www.byrdsight.com/apple-macint

Pete Foley worked on something similar while at Apple. See "Other Projects" at https://web.archive.org/web/20190102164746/http://www.byrdsight.com/apple-macintosh/ https://web.archive.org/web/20190102164746/http://www.byrdsi... and the picture "Turbo 6502" in the slide show at the bottom of that page.