Here is one concept I started on a long time ago, and I decided to pick it back up to add some details and clean it up. I saw this ship as a cross between a Miranda, Defiant and an Akira. It would be smaller than an Akira, with a Defiant-like bridge and nacelles, Akira-like pontoons and deflector and the Miranda rollbar. She still needs alot of work of course, but the basic overall shape is done.
What I did different with this one is the position of the bridge. Normally, I set bridges in the forward position, giving them a more agressive posture. This ship, however, had a pronounced deflector bulge and limited space to place it in, so the position of a forward bridge looked odd, and I decided to move it to a more traditional centered position.
Let me know what you think.