Just curious - why would anyone want a SECOND ark??
Ah - have you already completed the entire book and embarking on a second load?
Also, the shaping didn't prove anything of a problem to me - simply put a bit more stuffing in the cabin (so that it stands up straight) and a bit less inside the boat so there's room on the deck for Mr & Mrs Noah. The shape isn't so important anyway if the ark is going to be played with.