Specifically, the Kushan Avatar-Class Heavy Cruiser.
[Stats from the Homeworld Unit Viewer]
Mass: 800,000 tons
Firepower: 19,000
Armor: 70,000
Coverage: 80%
Manuverability: Very Low
Max Velocity: 190 m/s
Kushan Avatar Class Heavy Cruiser
If you think of Fleet Command as a Goddess-as most pilots in the Kushan fleet jokingly do--then the Heavy Cruiser is nothing less than a projection of divine wrath onto the mortal plane. The Avatar class Heavy cruiser is the most powerful vessel constructed since the Mothership. Over four times the size of a Revelation class Destroyer, the Avatar can direct more firepower than any ship in the fleet, and can absorb amazing amounts of damage while still remaining combat effective.
An excellent firing arc is provided by six heavy turrets, each mounting dual rail guns, each gun almost half the size of an entire frigate. While these turrets can engage and destroy more nimble opponents, even more fear is inspired by the four twin-mounted ion cannons. Against this kind of withering fire, even Mothership class vessels cannot stand for long.
Avatars are the stars of any Kushan fleet that can afford the massive resources required to build and crew them. The ship's complement--150 engineers, gunners and command crew positions aboard a Heavy cruiser--are the choicest assignments throughout the fleet, and even more vied-for than bridge positions aboard the Mothership. If there is an Avatar in the fleet, it will always be at the center of whatever action is occurring, and ambitious personnel can find no better place to earn distinction and recognition. Of course, while the Avatar is powerful and very heavily armored, it is not invulnerable--with every enemy gun trained on it, the Avatar's tactical priority is as much to draw fire from more vulnerable ships as it is to destroy enemy vessels. As a result, the repair systems aboard a Heavy Cruiser are the most sophisticated to be found in the fleet.
(From the crew compliment, I'd imagine it's fairly Miranda-class size compared to ST vessels.)
Are there any conversions? I have the model for the unit viewer. But it's a .SHIP format.