Yes, you can build a ship out of multiple shapes. And you don't even need to use "closed" geometry- FL's engine will handle objects that aren't closed- it won't draw the polys two-sided, but if you, say... had one sphere halfway inside another, it'd work just fine in the game(although you normally wouldn't do this because it'd raise the polycount needlessly...

Great...

I'm trying to create a new type of cruiser, but making it out of one block is such a pain...