I've found it, in a totally random unsurveyd system. I was like "ah, k, another fleet coming in... wwweeeelp, time to..." and then I've seen it. And it's broken, utterly so, it nuked 3/4 caesar class battleships in a matter of minutes, pratically the only ships that could go
toe to toe with it (to put it in prospective, two of them could take down, with some effort, a battlestation of any tech lev.).
Spawned it with consolemod, and has some 300 points for each one of the four "components", so it's quite tough.
Also, don't remember which mod adds it, but there is another "hub class" ship made out of 5 parts, 200 OP per part.
Not many examples, but they exists.
It could be implemented in the same way as the Caliph: fight the rogue fleet, beat the ship (somehow), and you get the hull, ridden with D mods that you have to fix through restoration (adding another layer to the challenge, we are talking millions and millions of credits).