On the moving of built things like a ship. I don't think that would be possible due to how the game is made. (I'm gonna be making assumptions again^^). I assume that the world works as blocks, as in there's only one way for a block to be in the world which is to be places in a set spot. These sports are not variable, but in a fixed grid and you can't be placing them outside the grid.
Moving a ship about like that just wouldn't work too well, it'll be jumpy and basically unfun. But what could be done is the creation of an object like the current boat, something that's free moving across the world. It's possible to add new ones to the game as shown in an plane mod (don't know the name, but it was shown on Yogscast's Youtube channel a while back).
So what we need is someway of 'tagging' blocks so that they become 'fixed' into a new object. It should be doable, but I've got no idea how much work it would take.