If it ever leaves the drawing board, the Saltire project would see a floating city carrying more than 7,500 people from California to the Caribbean within the next 15 years.
The model ship may look as if it came from a Thunderbirds set, but its originator, John McNeece, is a respected ship designer who helped to plan Britain's largest luxury cruise ship - P&O's 67,000-ton Oriana.
However, his previous work pales into insignificance when compared to this grand vision. Mr McNeece's ship would boast ice rinks, convention centres and helicopter pads next to the more traditional cruise distractions of shops and cinemas.
But such additions, Mr McNeece said, will be necessities. "As we become more accustomed to a hi-tech environment we will demand these things."
Launched at a Miami conference in March, the project has its British airing today. So far, the project has had a warm reception from ship builders.
"Sadly, there have been no earth-shattering changes in the look of cruise ships in the past 50 years," said Mr McNeece. "Certainly not compared with the aerospace industry."
The most radical departure from current thinking in Mr McNeece's plans is how the new design overcomes the "Panamax" problem. This is the width limit imposed on ships if they are to negotiate the Panama canal, which links the east and west coasts of the Americas, the cruise industry's most lucrative market.
The limit, of 32 metres, has meant ships being developed around the traditional single-hull "long-and-thin" design. But Mr McNeece's creation will be able to detach its four floating pads, and retract its stabilising arms, ensuring that the 200,000 ton Saltire can sail the tricky canal.
That this is more fiction than fact does not deter Mr McNeece. "The cruise industry needs more 'blue sky' thinking, more brain storming," he said.
"One thing is certain - the cruise industry 50 years from now will belong to those who invested, pushing forward the frontiers to make their dreams reality."
From smoke-stacks to helipads
For all its reputation for luxury, cruising has humble roots. The first "holidays" sprung up in the late-1800s and were nothing more than passages on mail ships for sturdy travellers who wanted to cross the Atlantic, writes Randeep Ramesh.
Then came the great luxury vessels of the Edwardian age - the most famous being the ill-fated Titanic. Tragedy apart, none of the great ships, including the Normandie and the Queen Mary, were financial successes. Cruising came of age only in the post-war years, with Cunard's QE2 epitomising the height of luxury. Now the industry ferries nearly 6 million people around the globe, and is growing at 8 per cent a year. Carnival, Royal Caribbean and the Princess arm of P&0 all have 100,000-ton giants on the slipway. But they will be like minnows beside the 250,000-ton behemoth planned by two American corporations - the pounds 800m America World City: The Westin Flagship.