I don't think you're going to find much available stock, and XS Scuba already had the last shipment coming to the US fully allocated to dealer backorders months ago. When I was calling around, I did find one single new Faber HDG HP100 at a shop in Detroit, but I needed a pair and wasn't passing through MI anytime soon, other than that, I haven't stumbled onto any existing stock recently. Certainly none of the big e-tailers have any left, you'd have to get lucky with a smaller shop, and they don't typically stock tanks in quantity, so finding a couple unsold galvanized in a popular size is a bit of a unicorn.
I ended up finding a pair of Faber HDG HP100 from a retiring public safety diver. I've been keeping my eyes open for a used pair for months, just happened to see a marketplace post at the right time, and he said like 3 other people contacted him offering to buy them.
Unless Faber finds a new source for hot dip galvanizing (they outsourced the hot dip process), it might be years before we see new hot dip galvanized steel tanks again, used market is best option at the moment.
If slightly shorter and slightly heavier works for your needs, you'll probably have an easier time finding some used Worthington HP100s, which have a really nice HDG finish as well. I like them for singles where the extra weight means shedding a couple pounds of lead. I popped into a shop while in Chicago a few weeks ago and they had 4-6 Worthington HP100s on consignment, they're out there.