I've read that Alan Buckelew (Princess Cruises president )has said that they have designed a new prototype that is based largely for the design of the Ruby Princess. "The new ship would be a bit longer and would comply with new stability rules," Buckelew says.
I also read that he said that there are no plans to make huge differences with the current ships as Princess like to operate a very consistent fleet.
Princess are looking at a number of shipyards including one in Japan.
As far as I am aware, no decision has been made yet.