I use a number of containers but my "go to" big containers are a two and three gallon glass containers. One had a spout, which I love because it makes it very easy to fill bottles. Once I fill it, I don't move it because it gets so heavy. I got both from HomeGoods. One looks like a big cookie jar with a lid, the other like a "sun tea" container.
But I'm at the same place you are. I want to brew bigger batches and I've been looking around at how the commercial brands hold their booch. I also visited a home brewing store.
A number of commercial brands use food grade plastic, as do home brewers. I'm going to give it a try, but I'm also concerned about leaking. The Home brew store owner said that only if the surface gets damaged should I be worried. I'm not so sure, but I'm going to give it a try.
I've also noticed that commercial brands use stainless french wine fermentation vessels. They are very expensive (from $250 to $750) and they would make so much booch, I'm not sure I could store it all.