Klavs has created an interesting image that shows the massive size and scale of the 22,000 meter Hvar'kann class dreadnought. It's pictured below next to the 983 meter Confederation class dreadnought. While the Kilrathi ship is more than 22 times as long, it is only several times as massive as its Confed counterpart due to differences in shape and composition. What could all that internal volume be used for? The full scale difference wasn't shown in the Wing Commander 3 engine, but the incredible size does play a major part of the novel False Colors.
Klavs' Hvar'kann model is available to download here.