I think that's where you're likely to stumble and fall with Lego. You're probably better off with the figures being a bit too large, like they are in the Star Wars sets. This is (at least) somewhat practical; a 5' long Scout/Courier is getting a bit large to be feasible unless you're happy to:
(a) spend a large amount of money on Lego exchange sites
(b) have enough room to build such an item (more of a problem here than across the ditch)
(c) don't mind impaling yourself on dropped Lego bricks for the next 6 years.
Well, not exactly
My AutoCAD drawings of the Type S, show the vessels maximum length as 33.4 meters (109.6 feet)
in 1/48 scale that is a model approximately 28 inches long
I am currently redrawing it with 14 inch thick walls (a single stud width brick) to see how much space I will actually lose in the deck plan.