Yes, I also had the AMT 3-ship set in mind. But I'm afraid I have slipped into the option # 1 camp (Hi, Albertese
), partially due to that "cockpit" intention in the original script.
While it's correct that the obvious analogy in the episode is that of a destroyer chasing a submarine, the vessel itself is not depicted as some kind of sea monster but as a flying bird of prey...!
It just doesn't have pylons like the Enterprise
but forward-swept wings
which could suggest atmospheric travel and planetfall capability (and has roughly the same size as the Romulan Bird of Prey envisioned for STFS before it turned into a Klingon BoP).
The Commander's wondering whether they still had nuclear warheads on board suggests that the vessel was stripped of weight, very much like the US bombers
in the Dolitle Raid on Tokyo.
We never see a ship wide announcement on the Romulan vessel (in contrast to the Enterprise
) and the only fatality the Romulans suffered appears to be the centurion (= small crew).
And last but not least the tail fin doesn't really serve a believable purpose, if the vessel was much, much larger. It is reminiscent of a ship's or plane's rudder.
P.S. Alternately the tail fin might be the Romulan's vessel excess heat dissipator / intercooler. I wonder how this would reflect in a size comparison assuming the width of the intercooler is comparable to that of a Federation Starship.
Another, previously unmentioned, analogy that rather suggests the BoP to have aeronautic than maritime qualities, IMHO, is its use to test a weapon of mass destruction (the plasma-energy projectile).
I had already mentioned the B-25 bomber Doolittle Raid, but failed to mention that the test of the new weapon is reminiscent of the atom bomb the Enola Gay
) used to destroy Hiroshima...