Since the new motion picture by Disney :/ will be relased this year I and I'm expecting a real hype when it's there I wanted to show you some preview pictures of my current Project:

The ISD Korruptor
A Victory I-class Star Destroyer (VSD)

Please note that this project is still at the very beginning and only the main reactor the tower and the basic exterior are done by now. The problem building this type of ship was, that there are little to no canon sources for it because it could only be seen in comics and games like Empire at War or Battlefront but never in any of the movies.

Nevertheless there are at least some very basic informations about the ship:

''The Victory I-class Star Destroyer, also known as the Victory I-class Destroyer and Victoria I-class Star Destroyer, was a warship designed for planetary defense, planetary assault, ground troop support, and ship-to-ship combat. It was used by the Galactic Republic during the mid-Clone Wars, the Galactic Empire and the Corporate Sector during the Galactic Civil War and the Confederation during the Second Galactic Civil War.'' (source: Wookieepedia)

The basic design is very similar to that of an Imperial-class except for the size: the VSD is 900 meters long whereas the ISD is 1600 meters long so almost double the size.
There are some other differences as well: The main tower has a very large bridge that is placed far in front of the rest of the tower giving it a very distinctive shape and allowing a better coordination with the two TIE -squadrons that are stationed on this vessel. While it has turbolasers and concussion missile launchers on the back for protection the Empire didn't put any efford in protecting the back of the Imperial Star Destroyers, because they thought no one would ever dare to attack the Victorys enormous brothers.
It also has two antennas on the tower giving it a little asymetrical look and a third, smaller dome on the back of the tower to have the back of the ship properly covered by shields.
The main difference to almost all the other vessels in the Imperial and Republic Navy however are the two ''wing'' sections at the side of the ship that enable it to enter a planets atmosphere to deploy troops and support them with its weapons. Only looking at a vessel of this size right above them in the atmosphere has an enormous psychological effect on most enemy troops fighting spirit and would have most of them surrender immediately, which is why the Victory class was used far longer by the Republic, Empire and New Republic than It's direct challenge: the Venator class produced by Kuat Drive Yards.

The vessel itself was designed by the engineering genius Walex Blissex, who had also designed the Delta 7 Interceptors for the Jedi order and later designed the new Republic class Star Destroyers for the New Republic. They were built by Rendili Star Drive, the producer that the Empire favored less and therefore started to support the Rebel Alliance.

That's it for now guys, I will try to update this soon. I hope you enjoy the first images though ;)