Supermicro boards go great in Supermicro 4U cases. I’m using an X10DRH-C in a case that holds 36 X 3.5" drives with a SAS backplane. You can grab a CSE-847 for 350 plus tax and shipping on ebay.

A set of cheap rack rails attached to some 2x4’s with a couple casters on the bottom and you have a rack you can stick in a closet and pull our when you need it.

The cheap rosewill cases are ok. But it you need to swap a drive (I have the 15 bay version that’s about 100 bucks I used for my server to begin with and now use it for a router with only two drives) it’s a pain to deal with. You have to pull the top, then remove screws to pull the cage for 5 drives, then pull the drive that you need to swap. It doesn’t sound like a big deal til a drive goes bad, or one of the 120mm fans that cool the drives dies.

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The Supermicro is the bottom one, the Rosewill is above it.