I don't know the square footage of this size feet, which matters the most to me. But last year there were three of us in a balcony cabin, we got the bed and there was plenty of room, both in the cabin and in closet space.
Carnival's cabins are among the largest in the cruise industry. I'm sure you'll all be quite happy.
You can go to http://www.cruisedeckplans.com/DP/Carnival/destiny.htm and see a sample room on the Destiny. It is approx 275 sq ft. We had this cabin on the Liberty and it was nice. Our long couch could pull out for a double bed. If that were done, there would be little walking room between the bed and couch/sofa bed. I don't know if you really need a rollaway unless they are big teens or older boy and girl. In the room we had 1 large closet, 3 large drawers under the tv area, a desk with more drawers and small side cabinets. Then in the dressing area, we had another large closet with shelves on one side, a vanity with more drawers but the best was the bathroom with a 2 sink counter!! The bathtub was narrow with sliding doors so it was nice not to have the shower curtain sticking to you. The tv has a dvd player so bring some movies to watch while relaxing or getting ready. Our balcony was long with 1 chaise lounge, a table and 2 chairs. Enjoy!
Teresa and Larry
#36-Carnival Splendor 9/16/12
7 night Mexican Riviera
#37-Allure of the Seas 11/11/12
7 night Eastern Caribbean
When booking, I learned that the cat 11 had a single convertible sofa vs. the double convertible sofa in the cat 12. We've got a 15yo girl and a 10 yo boy - so, while it may be a little cramped in the evening, I think the pull out may be best.
I wish I could call upon the magic upgrade fairy and just get that cat 12.
We had 4 adults in a Category 12 on the Triumph, had the fold out sofa and the trundle bed (slides up under the other beds during the day). At night, when the sofa was out and the trundle was pulled out, space was limited, but we all fit nicely. I can't imagine that a Cat 11 is much smaller than a Cat 12, so provided they just use the trundle bed and not a rollaway, you should be fine.
We had a Cat. 11 suite on the Glory last fall. It was very nice. It include a seperate dressing room and a "real" bathroom with a nice sized jacuzzi tub. It was basically the size of a balcony room and a half. There was extra closet space int the dressing room. An additional closet in the bedroom and more drawer space. The seating area had a sofa that converted to a bed and 2 chairs and an extra table. The balcony was larger and had 2 deck chairs a table and a lounger. This was an upgrade for us we had booked a GTY balcony. I long for another such upgrade, but I doubt that will ever happen again.
Enjoy I am sure you will be pleased!