Here's what I've got so far for presidential and VP candidates. Most of the running mates haven't been mentioned.
1948: Thomas Dewey (D-NY)/Harry Truman (D-MO) def. Harold Stassen (R-MN)/? (R-?), Henry Wallace (S-IA)/? (S-?)
1952: Harry Truman (D-MO)/? (D-?) def. Harold Stassen (R-MN)/? (R-?), Adlai Stevenson II (S-IL)/? (S-?)
1956: Harry Truman (D-MO)/? (D-?) def. Harold Stassen (R-MN)/? (R-?), William Averell Harriman (S-NY)/? (S-?)
1960: Hubert Humphrey (S-MN)/Warren Magnuson (S-WA) def. John W. Bricker (D-OH)/? (D-?), Harold Stassen (R-MN)/? (R-?)
1964: Hubert Humphrey (S-MN)/Warren Magnuson (S-WA) def. Henry Cabot Lodge (D-MA)/? (D-?), Walter Judd (R-MN)/? (R-?)
1968: Hubert Humphrey (S-MN)/Warren Magnuson (S-WA) def. James Rhodes (D-OH)/? (D-?), Bryson Briggs^ (R-NE)/? (R-?)
1972: Joshua Blackford* (D-NY)/James Rhodes (D-OH) def. Philip Ioannidis^ (R-NV)/? (R-?), Terrance Hobson^ (S-CA)/? (S-?)
1976: Joshua Blackford* (D-NY)/James Rhodes (D-OH) def. George Sidney^ (R-IA)/? (R-?), Dwight O'Hare^ (S-NY)/Carl Martin* (S-CA)
1980: Morgan Reynolds^ (R-BC)/John S. Smith^ (R-?) def. Mildred Morrell-Quigley* (D-KS)/? (D-?), Theodore Abner Abell^ (S-?)/? (S-?)
1984: Morgan Reynolds^ (R-BC)/John S. Smith^ (R-?) def. Porter Schmitt^ (D-IL)/? (D-?), Robert Bronowski^ (S-PA)/? (S-?)
1988: Leo Enos* (S-MA)/Alfred Turnbull^ (S-ON) def. Archibald Young^ (D-MN)/? (D-?), John S. Smith^ (R-?)/? (R-?)
1992: Thurston DeFrancis^ (D-CA)/? (D-?) def. Patrick Gutierrez^ (R-NM)/? (R-?), Alfred Turnbull^ (S-ON)/? (S-?)
1996: Patrick Gutierrez^ (R-NM)/? (R-?) def. Thurston DeFrancis^ (D-CA)/? (D-?), Jonathan Wyden^ (S-MN)/? (S-?)
2000: TBA
2004: TBA
2008: TBA
* = Fictional character (HT)
^ = Fictional character (DBE)
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I assumed any non-canon character who I couldn't find a Wikipedia page for was made up by you, David. (Are they friends of yours?
) I found a George Sidney, but I don't think he's the one you were thinking of.