Re: U.S.S. Curry and other ships from DS9
^^^ As I mentioned in a previous post (I was probably typing it at the exact same moment you were typing this
), they were probably left-overs from an unfinished Nebula prototype
(like the original Melbourne) stuck in a drydock somewhere. It has smaller engines that look like they would perfectly match what's on the Trieste, scale-wise.
I may appear unoccupied to you, but at the molecular level, I'm really quite busy.