I've not seen many 'mahoosive ships' ( eg Lightning class) other games are a good source.
Not quiet on topic, but other deckplan sites I have found...
http://wavesintheblack.aimoo.com/
waves in the black boards for the serenity RPG. some serious high quality stuff there in the starships forum, and a couple of familiar ships rejigged as well. Treat the pulse drive as a jump drive and you only really have to convert the stats.
However some of the heavier alliance ships from the movie have been tackled but its more a designatoin of areas on a standard side and elevation plan. You will need to fill areas with slot in sections.
Also serenity, a damn fine used ship lot!
http://www.awtry.com/RPG/Ships.html
Again, your usual far/fat/free trader area in size.
Howeversome larger ships can be found. Star wars ships here, universe cannon and non cannon, click on the image for the deck plans.
http://www.colonialchrome.co.uk/Ships.html
Some are more like the 600 ton subsidised liner to about 1-2000 tonners (speaking in traveller old money)
Also the following:-
Deckplan alliance
http://deckplans.00sf.com/
Design alliance
http://swda.art-of-void.de/weblinks.html
All suffer from the adventurer size ships
Those Future Armada are serious top quality. d20 stats, but those can be discarded or converted. Worth getting a paypal account and buy them.
Also worth looking at getting the T4 Naval Architects Manual that has lots of sections to slot into your megabattledreadnought carrier