Have just read this article about the swedish shipping company "Dejlig Cruise AB". The company has long worked on the development of a unique vessel in the winter to serve as product tanker targeted vegetable oils, and in summer as passenger ship across the Kattegat and Skagerrak to Skagen.
Passenger accommodation will consist of modules that can be removed when the ship goes in tank.
The company have just recieved the Shipping Innovation Award of 350,000 SEK from the Swedish Shipowners' Association for the development of an entirely new type of ship, a multi flexibly combined tanker and passenger ship. Delivery in 2015.