If the movie cannot be used for establishing the size of the ship, I declare her five and one-quarter inches long. And that's definite. I got it from an authoritative source that trumps all of yours: my very own computer screen, faithfully reproducing preproduction artwork.
Of course, both the STXI and TOS ships have definite sizes established on screen. Several sizes, in fact. The STXI ship has her size established by comparison with her shuttlecraft which are of known size, and by comparison with crew of known size peeking out of windows. That's two sizes already. The TOS ship has her size established by comparison with her shuttlecraft, too - but before TOS-R, the only way we could make that comparison was by comparing the shuttles against the insides of the bay doors, since no exterior views existed. And then her size is established by comparison with adversary spacecraft, of which exactly one is of known size - the cube from "Corbomite Maneuver". Again, those give two very different sizes.
Which may be enough of a reason to close your eyes whenever watching Star Trek, and instead read the definite statements of her makers. In which case the five and one-quarter inches size stands triumphant. As does the 716 m size. And several others. So perhaps we don't actually win all that much by taking that approach...
Timo Saloniemi