Oh wow, I just bought mine here in mid-October '19, very recent:
https://www.amazon.com/gp/product/B000I5JHB0/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
Now it says 'unavailable', so they must have JUST discontinued it. I *believe* Newegg sold it in October, too, but I went with Amazon because it was cheaper. I guess they finally discontinued it starting in 2020 or late 2019..
Think you'll need to dig around for it and see who has stock left, it seems some people do, this is $150 shipped new via Ebay:
https://www.ebay.com/itm/Antec-Nine-Hundred-Black-Steel-ATX-Mid-Tower-Computer-Case-with-Upgraded-USB-3-0-/153764530849?_trksid=p2385738.m4383.l4275.c10
Yeah, the pickings really suck now, it's crazy. The Antec 900 can give you 12, but apparently just discontinued, so pick one up while you can find one.
I've never heard of it before, and know nothing about it, but there's an "Antec One" which has 8 bays, which could give you 10 3.5's with the 4->3 bays, or 12 drives if you go with one of the few 5->3 options.
https://www.amazon.com/Antec-Mid-Tower-Computer-Pre-Installed-Mini-ITX/dp/B006TVQU6C
Also, since you don't care about hot swappable bays, you can go with the Antec three hundred, which will give you 9 bays w/o any additional drive bays:
https://www.amazon.com/Antec-Three-Hundred-Gaming-Computer/dp/B000GQMHBI
This is the one I like the best if you don't want hot swappable, the P101, 8 bays native, easy to remove them:
https://www.amazon.com/dp/B07LBXP8KZ/ref=twister_B082HRQ9B2?_encoding=UTF8&psc=1
All these Antec options I feel like a fan boy, but they seem to have many of those style cases for it.
One case I almost bought instead of the 900 was this Silverstone which is cheap and has 8 hot-swap bays built-in for low $$, the only reason I didn't go with this one is because I didn't want to be tied to a particular back plane if it didn't work out for some reason (ie. say a port died). Though that's just me being kind of paranoid I think, it looks like a very good case for NAS purposes:
https://www.amazon.com/SilverStone-Technology-SST-CS380B-USA-Computer-CS380B-USA/dp/B07KTCSWPP