My thought is that Romulan stations should be a bit behind Fed/Klingon stations simply because they're resource poor. So, smaller stations but sharing some design characteristics with whatever design would work best in the environment it's placed in. So something based off K-7 for instance would be smaller, but have a shorter neck, the typical Romulan embellishments, and maybe a ring joining the sections. I'll see if I can grab a couple of pictures to mock it up..
No ring on it, but this gives a good idea of the derivative (ie: pilfered) tech that I think they'd use, in this case around TMP times. After all, using someone else's R&D and tech that's proven as a basis cuts down their deployment time. My personal belief though is that the Romulans follow a form of bushido.. they'd bribe someone for the plans, and steal only if they were forced to do so. But a promise made to someone outside the Empire is a promise to a "non-person", about the same as promising something to a dog or a cat. Not something they'd have to live up to, but would if they could.
Just a personal belief though, think that TNG made them more sneaky in general.