Quick sketch of how I'd like my destroyers. (Shaken, not stirred) The UNSC Heart of Midlothian doesn't look like a standard UNSC design (in my opinion anyway) , and has a butt-ugly aft section, and the Genesis graphic novel looks poorly drawn or rushed. I like the art style they used for the destroyer in "The Babysitter" though, has a weird nostalgia-80s-mecha feel to it, although it looked like a stretched Halcyon.
Anyhow, this is a sketch. May have more concepts popping up later on, and may decide to model it in the near future. Tried to keep close to the descriptions as possible from Eric Nyuland's books (ie the destroyer's proportions are similar to the frigate, no hangars for snubfighters, heavy armor and dual MACs). Also had some nifty base in mind from my earlier Ranger-class UNSC Destroyer some time back, pretty much just a modified Frigate model. Might give it a cruiser-y feel to other concepts, bridging the gap between the Frigate and Cruiser designs.