Actually, I found a way to add ‘duration’ to the sorting parameters in iTunes.
Shortest track appears to be a 5-second John Williams bumper from the first AMAZING STORIES 2CD set.
Longest track is a ‘cheat’, because it’s a rip of a radio broadcast of a concert (the track is 1:33:58). But the longest PROPER track is – indeed – a Jean Michel Jarre track. Two, in fact: First “Snapshot 1, Part 3” from EON (an album that is only part of a rare, extremely expensive box), at 51:54, then “En Attendant Cousteau” from WAITING FOR COUSTEAU at 46:56, and – for film music – the single 41:45 track “Chronos” from Michael Stearns’ score of the same name.