I realize this is pretty obvious, but it is odd that no one seems to be asking for bigger hulls. The HUGE hulls are pretty slow to make, so obviously a "GIGANTIC" hull would have to be very slow. It might be fun, though, striking fear into the hearts of your enemies with something it took years to build. If they were, say 120-150 spaces, and took 3x as long to build as a HUGE hull, they wouldn't be horribly debalancing to the game.
I dunno... anyone think that would be fun?