I think that the second one here makes a nice transition from the KR to a later design...
![](http://www.frost-works.com/watchtower/Sketch%20Romulan%20TOS%2000.JPG)
...and this one makes a nice transition from the Skyhawk design.
All of them are good. Those two are just my favorites.
Are you thinking of doing the meshes yourself? I think that you should, personally.