a little late to the party. well probably way late, but maybe if someone is still needing them... we used food grade 5 gallon buckets for our rooftop garden last summer.
i didn't want to divulge our source at the time for fear we needed more, but we were able to score "all we could take" of the buckets from Rich's Deli on western (south of Augusta). they were the buckets that their bulk sauerkraut came in, so they needed a good hosing down in the alley first. they told us to come back for more if we needed. i'd imagine other similar polish deli type stores might have them too. drilled a hole in the bottom and they worked remarkably well. they were solid white, too, so it had a kind of modern look to it when they were in rows