What I was taught in political science classes was that the last realigning election was 1932 and that there will likely never be another one, largely because the advent of public opinion polling allows parties to gradually move, rather than the sudden re-divides of 1824, 1860, or 1932.
-1932 was not a constituency realignment (FDR's constituency wasn't much different from Wilson's), but an ideological realignment, and, indeed, it was the last such one in American history. The age of Reagan only began the trend of the dying of the liberal Republicans. Trump could bring about an ideological realignment, but I'm skeptical.