(It wasn't a deliberate creative decision either, to be honest I don't know how it happened - I assume I connected the red and white plugs up correctly, maybe my SCART adapter is wired backwards.)
Anyway, I authored a short 1m 30s sample to a DVD+RW last night to check compatibility with my DVD player, and I was very happy with the quality on a 28" widescreen CRT TV.
That's the good news. The bad news: I estimate it's going to take about 60 hours to do a 4-pass encode on this sucker...