The Breen are an interesting race in the ST universe. Their ships are partially organic and they are apparently a very Machiavellian race. Class for class, their ships are smaller than the corresponding ships from the other factions in the Alpha quadrant, however, because of their energy disruption weapon, they can be particularly deadly. Here is a size comparison of all the Breen ships (the Tha Taan, the "official" Breen ship, is the second on the right). I tried to capture the design aesthetic of the Breen with a large boom on the right, sweeping curves and the asymmetric design. I think the unofficial ships capture the aesthetic well and the ships look like they were created by the same race. It does make a impressive fleet.