Customization for Hull.

Not just the Livery, but the Keel, Hull, Masts, Rudder, Deck, Railing, etc; the entire ship. This doesn't have to be separate - it'd be a pain if it was. We can already have different sails, wheels, cannons, and the like; I just think when changing the Livery it could change the ship into something suitable as well. I don't know about you, but I'd love to see a broke-down bilge rat ship vs a sovereign one.