If you go look for a used regular PC case, older model will typically have more 3.5" bays. By older, I mean +15yo.
If you have access to a 3D printer, you have options to make more drive bays on the cheap.
You will have to go for a modern power-supply still, in order to have enough SATA power plugs.






Not exactly cheaper to get than a Jonsbo case.