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.
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.
It is huge. it fills the full volume of an Ikea Kallax opening, I have mine hanging out so wires in back against the wall have some room...plus some airflow.
if the Kallax wasn't against a wall it would slide back all the way. It has plastic feed about 12-15 mm tall (I think) feet are about 3mm too tall so I trimmed them. But on thingverse somebody made a 3d printer model for replacing them.
I know lol, I went from a little baby Silverstone itx case to this monstrosity. I love the modularity of it but it's just so big. I don't think I'll go back to itx, it's honesly a fucking pain, but I'm probably getting a slimmer case.