I just was at the local outfitter - the one where I noticed the low-stock condition initially. They now had a full supply of canisters.

It's starting to look like there isn't a real problem, but that I may have just hit them as they were learning to live with the rules.

However, there doesn't appear to be any chance of getting canisters online any time soon. I'm lucky - I'm half an hour from the store, and frequently work in the city, so it's not a problem to get them when I need them. But, for anyone who is limited to online supply, it could remain a real PITA.