Cas.. the weight of such a thing would make it impossible. If you take a look at any of the recent attempts, you will see what I am talking about. Even the Hindenburg which is one of the largest every constructed couldn't carry a cabin space larger enough for more than 100 people (36 passengers and 61 crew were on the last flight)
Although the accommodations were very nice, there is no way that it could be cost affective.
Carnival Cruise Lines:
Fantasy 90, Celebration 95, Victory 05, Conquest 05, Spirit 6/06, Freedom 6/08, Holiday 7/08, Victory 6/09, Valor 9/09, Dream 6/10, Splendor 8/10,Conquest 8/11,Magic 11/11,Triumph 4/12,Spirit 7/12,Freedom 11/12, Triumph 2/13 - The fire cruise
NCL Dream October 2006, RCCL Mariner OTS June 2007