^Interesting list. I do have to say I don't think HW Bush would've been the VP in '80 in this primary scenario.
Perhaps. An interestingly wacky idea for Reagan's 1980 running mate would be Donald Rumsfeld. At that time, relatively young to offset Reagan's age, but still pretty experienced. Sort of like a mirror version of Bush, in that he'd served in the House, as well as numerous positions within the Nixon and Ford administrations (most significantly, Chief of Staff and SecDef for Ford).
Reagan/Rumsfeld in 1980 of course sets up a possible Rumsfeld/Cheney ticket in 1988.

Someone should write a President Rumsfeld timeline.