Okay, this ship is HUGE.
It is a 1:1 scale UNS Battleplate "Tunguska" from the series Schlock Mercenary
10,371,362,793 credits
46,119,616 Ogonite
632,894,126 Avorion
1.28 billion hull
437 million shield
~27 billion m3
1.16 Gt
Requires nearly 1 million crew and 330,425,050 Cr upkeep.
Steam Workshop link
You will probably need creative mode and some modded extended range weapons to actually use it, but you can suppress an entire sector with one of these. Anything you cannot kill immediately you can either outlast with 400,000,000+ shields or you can let them bounce off of your hull with minimal damage. You will also need to stack some hyperspace cooldown modules so you don't have to wait almost two hours to recharge. On the other hand it only takes three jumps to the core. Have fun!
UNS_Tunguska.zip