Reagan, of course, died not long before the convention, so the big tribute was no surprise. That said, the Gipper got a big tribute again in the 2008 RNC, while Gerald Ford, who had died more recently, was part of a video tribute to "Deceased Republican Leaders and President Gerald Ford." You could look at that and think Mr. Ford was getting the same treatment Ginger and Mary Anne got in the theme to "Gilligan's Island," but I think it's just the recognition that the Gipper is still the Gipper in American politics even if he's been dead for nearly a decade. The Tupac of dead presidents, essentially.
The other convention tribute that jumped to mind was in 1964, when Democrats made the late President Kennedy a centerpiece of their convention. And the centerpiece of that centerpiece was the speech by JFK's brother/Attorney General, Robert, which he was only able to give after some 22 minutes of sustained applause:
RFK, says one of the speakers in this clip, "was the representation of what they had lost." Between this and President Lyndon Johnson's calls to "let us continue" President Kennedy's work, the Democratic ticket did anything but lose in '64.
I'm still looking for detailed schedules of past conventions - it would be interesting to find out which late and/or former presidents were feted at their party's conventions and which weren't. One suspects President Lincoln was a big presence at the 1868 Republican convention, but one also suspects William McKinley didn't accept his nomination in 1896 under the shadow the departed Rutherford B. Hayes. Maybe they had a video tribute in honor of departed leaders and General Hayes? You never know.