Specs are slightly in flux right now, but basically it's an HP ML310e Gen 8, with a random HDD cage on top for 4 additional drives, and a bunch of fans zip tied to the front to cool the 6 internal drives. Oh, and a little 7" display stuck to the side which I'll get a stats readout on soon.
Xeon E3-1220 v3, 32GB ECC RAM, 40TB array, Quadro M2000.
It's running Unraid and I use it as a media server (Plex, Sonarr, Radarr) as well as a backup for my music and video production, and general stuff (NextCloud, Photoprism).
The machine itself is so stupid and hacked together, built entirely from used parts I got cheap on ebay. It's probably cost me £300 max, all in.
I just grab them off ebay. SAS drives are almost exclusively used in enterprise servers, so there's fuck all demand for them on the used market. Buy a cheap PCIe SAS controller card and you're good to go.
I use Unraid which doesn't care at all about what types of drives you use, so you can mix and match into one huge array. I have 8x SAS and 2x SATA drives in one array.