Yes. Ran a 3E/3.5 campaign (converted partway through) that primarily used the original WotC "adventure path" modules (Sunless Citadel, etc.), that went from 1st to 20th. Three of the four original PCs made it the whole way through (one player dropped out at around 4th level; his PC was replaced by an NPC).
Am currently running two 3.5 campaigns that started at 1st, and intend to go through 20th.
Never seen anything remotely approaching 20th and probably never will; best I can give you is the same character going 1 to 11 and still active...scary thing is, it's mine, and I usually go through characters like a paper shredder.
A more useful question, and tie-able in-able to any edition, might be what's the longest character career you've seen in terms of number of adventures. This is obviously harder to define in some campaigns than others, but for example someone who'd gone through the 8-adventure path noted earlier and then quit - assuming no side adventures - obviously had an 8-adventure career. (disasters like The World's Largest Dungeon kinda wreck this concept...)
Using these criteria, the longest career I've seen is 32 adventures.
Yup. The one that immediately springs to mind was a long-running 2nd ed campaign. Started as a cleric of god A, had a crisis of faith, dual classed into rogue for a while, eventually got back to cleric but of god B.
I remember the game only had 3 pcs. My cleric, a fighter/rogue, and an enchanter.
Nope. Closest I've gone was a character who started around level 10 (might have been as low as 8, but I think he started at 10) and ended up getting retired around level 16-17.
I did run a campaign from levels 1-14, but that's as close I've ever come to that sort of thing. Of course, we could always go back and do other things with those characters, but there wouldn't be a large, overarching plot pushing the action.