Well, I guess this stuff does really exist, my 22 quarts of M1 5W40 arrived today. I ordered it at $6.99/quart about a week ago (free shipping with $150 order) from these guys:

http://www.autobarn.net/oiladditives.html

They were a little slow, but they delivered. I guess I'll just order it in $150 batches until I find it locally again.