Yeah I believe the Fantasy Class ships (unfortunately), and Holiday Class ships do not have connecting rooms. However, the mega ships-- Destiny Class, Spirit Class and Conquest Class ships should all have connecting rooms. The Celebration is considered a Holiday Class ship and does NOT have connecting rooms.
I would like to suggest the Carnival Triumph
07/30/95 - Fantasy
12/19/97 - Ecstasy
07/26/99 - Imagination
04/01/00 - Grandeur of the Seas
04/01/01 - Carnival Victory
03/29/03 - Carnival Triumph