The Stingiest Man in Town (1978)
This is actually an animated remake of a live action musical version (also a TV special) from 1956. It's full of songs and music; there's actually very little dialogue. I really like the music, although bear in mind the style has a lot in common with old-fashioned movie musicals.
Some of the songs are wonderfully surreal. Near the start, Erin asked me to confirm that we'd just heard a bunch of alley cats singing about how Scrooge was so stingy that Satan was going to complain about him in Hell. Yes, yes we had.
They manage to fit digressions about both Santa Claus and Jesus into an hour-long Christmas Carol, so there are a few common scenes missing from this adaptation. Nothing about young Scrooge at school, and if you blink you'll miss the Ghost of Christmas Future.
I like the voice acting most of the time, but the animation is too uneven to really support it well. It has strong moments, but the low budget shows, and there are occasionally very ugly sequences that might be caused by miscommunication with the Japanese animation studio about the character designs.
Even so, I'm glad I tracked this down. If you're looking for a unique Christmas Carol, and you like musicals, you might enjoy it too.