Been looking for something similar, but finding anything with 5.25" bays these days is difficult. This Silverstone case might be close, but the 4 bays aren’t contiguous and it is big enough for an ATX board (and/or rack mounting, apparently).
So they have to be 3 together. Then you can get 6x2.5" drives in a single 5.25" bay.
So ideally you want 4x5.25" bays, with at least 3 of them in one block. Or some 3.5" bays and a single 5.25" bay.
I’m actually reconsidering the mATX requirement. There are some cheap but good ITX boards available from Topdon that are ideal for a NAS. The CPU isn’t super fast but it’s enough (it actually performs quite similarly to my current Xeon based server/NAS), and it’s decently speced while also being low power.
2xNVMe (but only PCIe3x1)
PCIe3x1 slot
6xSATA 6Gbps ports
3x2.5Gb ethernet (2xIntel and 1xRealtek)
It’s also got a console port, just a shame that Windows Bitlocker doesn’t support entering the password over serial. But you can admin the BIOS and a suitable Linux system with only an RS232 connection. Ethernet/wireless RS232 servers are a lot cheaper than KVMs.
This one caught my eye too. 3.5" hot swap bays built in. If they replaced them with 5.25" bays, or even just put a 5.25" bay above them, that would be great. Remove the PUU and put the motherboard vertically in that space.
Just tripped over this one – 7 external bays, mini itx. It’s kind of a deep case, though, as it would have to be. There’s also apparently a 5-bay one (s-915), but frankly that one looks even more cooling compromised than this one does.
The door appears to be screwed on, so could be removed to improve airflow.
It says it is an ITX case, but it looks like a full size ATX board will fit. Certainly an mATX board. You would just need to relocate the PSU, or fit a smaller one. I was thinking of using a PicoPSU anyway, as they are more efficient.
The 5 bay one looks really nice too. I’ll have to do some measurements.
The only issue is that they don’t seem to sell them in Europe or Japan. I could import one, it won’t be cheap… It’s the best option so far though.
At least it’s available though. I only found one place in the US where I can order the iStarUSA one that does international shipping, and it’s on back-order there.
Bargain price and 4x5.25" bays. I used to see those back in the day, and they really are built down to a price. Cheap, thin metal with lots of sharp edges. They rattle a lot too.