I was just at Target and they have a 2 gallon glass jar with lid from Anchor Hocking; it looks perfect for vinegar making. I'll just make a standoff for the lid if necessary. (Getting the acetate 'mother' out of a carboy can be a lot of work, mine are very thick.) 2 gallon batches are about the perfect size. I'm sure these are available elsewhere too; they look like the thing you would run into at the bargain stores down the road.
Joe