I fear that this obsession with deck plans, be it from ADB or Mongoose, is creating an artificial barrier to publication that is unnecessary. Deck plans are certainly nice, but not necessary to enjoy the game.
Traveller will always have the gearheads, those who want to use the game to build ships or vehicles or planets. But at its heart Traveller has been, and (hopefully) will always be a RPG. RPGs are games for the imagination. I recognize that from early times Traveller, likes many other early RPGs, had its root in wargames. It seemed like in order to play a good gamemaster had a ship/dungeon laid out for the travelers/adventurers to battle on/in. Remember CT Azhanti High Lightning with all the decks laid out? Or Snapshot? Useful for those adventures/wargames but not that great for RPG play. How about the deck plans in MgT High Guard? Useless for play...and I would argue not necessary at all. Better to have good visual representations of the ships (pictures, art, graphics....but NOT miniatures ala Traveller Babylon 5!) that evoke the imagination. Really, do you play "you are running down the corridor but given your speed you stop 4 squares short of the door...next player" or "as you run down the corridor, you are almost to the medical lab when the door opens...what do you do?"
I'm sure many of you haven noticed the evolution in RPGs that has come from the Narrativist approach to gaming. Part of this approach is to use maps as general guides or maybe not even at all. Take a look at the new Edge of the Empire Beginner Game and you find maps that use tokens to track general relative positions or Marvel Heroic Roleplaying that avoids a map and uses sticky notes in the example of play to define the area of the battle. What I'm saying here is the maps don't have to be super detailed but spurs to the imagination.
That said, as I flip through my PD collection I found the following deck plans:
Federation Burke-class Frigate
Free Trader with variants
Klingon G-1 Gunboat (both in books and has standalone deck plans)
Romulan Skyhawk Destroyer
So a few plans already exist...but are more really needed? Think of the various TV series locations. For the major ships you had the bridge, medical, engineering, crews quarters, and rec spots (holo deck, 10 Forward, Quarks Bar, etc). There are a few others but maybe one can get the sense of a ship from a few smaller maps. Since everyone seemingly wants to play a bridge crew, why not have a vast, spacious Federation Bridge, a cramped Klingon Bridge, and that interesting Romulan one where everybody stands around the center console. Don't need the whole ship; just some locations to spur the imagination.
Bottom Line (finally): I say give us the product using the deck plans that exist and let us play. If we really want deck plans those can follow.