I haven't found any 0W-20 in a 5-quart jug. Pennzoil says their Ultra will be available in 0W-20 next year, and because that'll be a new grade for that oil I hope they market it in the 5-quart jugs (as well as the quart bottles). Mobil 1's AFE is in 0W-20, but it's in quart bottles only. Mobil has been asked about 0W-20 in larger jugs, so maybe they'll see the market demand for it soon.
Until then, it's gotta be in quarts. If you're interested in Toyota's 0W-20, check your dealer. It's surprisingly cost-competitive...cheaper than the Mobil 1 0W-20 at Walmart!