RCI, Mariner of the Seas #1690 and 1390 on deck 10 Category D1 - same price as other D1s. Aft cabins are wider and longer with much more walking room, balcony was double width and length holding 2 full lounge chairs, 2 regular chairs and a small table. Also, #1688 and 1388 (corners Port & Starboard) are much wider cabins with a pole in each cabin but a porta-crib plus a pull-out sofa are accommodated well. Balcony is wider and a bit longer, but the steel hull does cut the periphial view and space. As you go down each deck, the configuration does change and the cabin & balcony sizes are smaller.
Carnival Pride & Legend, #8232 (?): There are a total of 6 extended balcony cabins but 3 are designated HP on the striped decks. When looking at a deck plan, look at the rear bank of elevators. Those cabins that appear on the Port side near or beside the elevators are actually separated by a stewards ice closet; no elevator noise. These balconies were triple length from right to left not width and were also great. They had two full lounge chairs and two regular chairs with a table.
Celebrity Millennium; FV cabin Port & Starboard aft corner (#7??? cabins). This is a two room cabin with divider but one bathroom. Closet space is fabulous, plus there is an entry hallway for storage and two door bells. The balcony was triple width and length plus the veiw was aft and port side with no obstructions. There were two lounge chairs, 4 regular chairs and a patio sized dining table. The Living room had 2 sleep sofa's which converted to accommodate 3 children. However, our 3rd child was 12 yrs. old and they would not allow her to room with her two younger siblings as they considered her an adult. If Nana wasn't cruising too, I would have questioned if she would have been allowed to purchase her own cabin, but she roomed with us right next door in a triple. These cabins are right above the Presidential Suites. As you go up a deck level, the balcony is recessed thus slighty smaller. People can be seen from above if they are standing or lounging nearest to the rail.