I do know that Carnival has some ships that they will put 5 in a cabin, but not all of them. We were hoping that our friends with three children would be joining us in November aboard the Carnival Legend, however, they will not accomodate 5 per cabin on the new Spirit Class ships (Spirit, Pride, Legend). The only option was to book 2 cabins in which case they would have to pay full price for four of them (1st and 2nd person in both cabins) and would get the 3rd/4th person rate for only one person.
This made a considerable amount of difference in the price, and unfortunately they will be unable to join us this fall. We chose this cruise for the itinerary rather than the ship. Glad there are only 4 of us in our family - makes things a lot easier.
Our TA has informed us that the Carnival Victory has cabins that will accomodate 5 people, so we are looking at that for November 2003 so all of us can cruise together.
Good luck,
kp