Another song that could go on painfully long if you included all the verses is "Battle Hymn Of The Republic."   I usually sing 5 or 6 verses when I do the song, depending on the setting, and even then I'm including 1 to 3 verses that most of my audience doesn't know. (They just join in on the chorus.) But I think Julia Ward Howe wrote at least 10 verses to it.

John Newton also wrote umpteen verses to Amazing Grace (not including the "... ten thousand days ..." verse, which someone (J W Howe?) added later.   Nobody sings even half his verses, do they?

The US Civil War song "Lorena" is a favorite of mine, and, as originally published, it has 6 verses. No chorus, but the last line of each verse is repeated.   I used to do the whole song but found people remarking about what a long song it was, so I dropped the 4th and 5th verses, and the story comes across very well without them - plus that leaves time for the instrumental breaks by the banjo, mando, fiddle, guitar, etc., to fill up the rest of the 10 minutes. ;-)
John Hartman (sp?) does a wonderful version of this song, using only the first 3 verses and not repeating the last line of the verse, but playing the whole tune on banjo between verses.