As much as I'd like to help you, I'm not sure the stuff you're looking for exists; if you find the Standoff
models too low-resolution, there's probably not much better you can go. Most of the models produced for the entire series are around that quality; the 10,000+ poly models are very, very rare.
If you want someone for the supercruisers, though, I can probably help you out a bit. There's very little good material for the bottom and rear, but this making-of-video for the movie intro shows a good fore view: http://download.wcnews.com/files/wcm/on_camera_art.wm
(The actual finished movie intro has a similar shot as well, though I believe it's a different one.)
As for the aft section, it's hard to determine, but it's important because the fighter bay is located there. If you zoom in during the panorama at Pegasus in the beginning, it looks like it opens up directly aft (like on the Victory and Lexington, except there's no forward opening to fly through - I think Standoff portrays escort carriers the same way, but in that case I believe that was a result of technical limitations). Directly above the hangar entrance-exit is where the third engine port of the ship looks to be located.
That's about all I can give. I made a model of this once, but it's pretty messy and the forward ventral section is all guesswork.
Oh, and there's also this: https://www.wcnews.com/articles/art29.shtml
. Good look at how the ships evolved, even though very few of them remained that way.