Hmm ... a TOS Constitution class upscaled to 327m and a TMP version with the official 305m. Or maybe we can scale them so that their saucers are of the same diameter. I think that could be feasible. I like your idea of cutting parts of the hull away and streamlining the ship. Although the TOS ship needs to be upscaled to around 327m to solve certain problems with it (see this thread: http://www.trekbbs.com/showthread.php?t=89810
), and for the saucers to be of the same diameter the TMP version has to be upscaled a bit too.
A few notes to Mytran's post:
(Slightly) irregular window levels don't speak for a bigger ship either. Especially in the engineering hull, where a few higher than normal decks wouldn't be that illogical. Only really huge irregularities would speak for a much bigger ship and I don't see them on the Constitution class.
Regarding the bridge, why should it not be partly submerged into deck 2? What speaks against it? The bridge of the Excelsior also has to be submerged. It's just not really a problem. And I think more than one person has already shown that with just a little bit of upscaling, the bridge might not need to be submerged at all (like Cary L. Brown in the thread I posted a link to above).
Regarding the shuttlebay, we saw the shuttlebay door from the inside and outside, and we saw details inside the shuttlebay we could scale it to. The results wouldn't be absolute because we don't know the EXACT size of those details (I think there are different figures for the TOS shuttle for example), but it gives us a reasonable range.