I'm having trouble finding a 3 gallon food-safe brewing pail bucket for half batches.
Bakeries and donut shops.... I get 2 gal, 3.25 gal, and 4.25 gal pales from them. I've used the lids they come with but most are made by the same people who make the Ale Pails so those lids fit as well. They don't always seal well enough to make your airlocks work, but they don't present infection problems either.