Passengers boarding at London Euston should feel they are stepping into Scotland as soon as they enter the revamped train, with everything from the food to the decor being "emblematic of the very best of Scotland".
The challenge was made as government agency Transport Scotland set out the minimum requirements it expected the successful bidder to deliver in exchange for more than £50 million of public money.
En-suite toilets in business class berths, wifi and electricity supplies in every carriage, and secure luggage storage for all passengers were among facilities demanded as the Caledonian Sleeper prepares to undergo its first major overhaul in more than 30 years.
It is the first time that the sleeper service has been split off from the main ScotRail franchise, an indication of the Scottish Government's desire to see it run and marketed independently from the rest of Scotland's rail network.
The three shortlisted bidders were unveiled in June as First Group - which currently operate the ScotRail franchise, including the Caledonian Sleeper - Arriva Night Trains Ltd, and Serco Ltd.
Arriva is owned by German state railway company DB, which operates the largest network of sleeper services in Western Europe, while Serco operates sleeper trains aimed at the tourist market in Australia, including the Indian Pacific between Sydney and Perth.
They have until the autumn to finalise their blueprints for the service, with the winning bidder appointed next summer.
The winning bidder will take over the franchise for 15 years, beginning from April 1 2015.
Transport Minister Keith Brown said: "The Caledonian Sleeper provides a service vital for connecting communities across Scotland and beyond, and helping attract visitors and business to key destinations right across the country.
"The sleeper is already a convenient service providing accommodation for budget, family and business travellers, and accessible for all. Demand has grown since responsibility for the sleeper was devolved to the Scottish Government.
"Now is the time to do more."
The Caledonian Sleeper is the longest passenger train in the UK, carrying some 270,000 passengers a year, six nights a week, between London Euston and Aberdeen, Edinburgh, Fort William, Glasgow and Inverness.
Ambitious plans to modernise it come less than two years after fears that the service - which operates at an annual loss of about £5m - might be scrapped.
The news outraged high-profile fans including many politicians commuting between Westminster and Scotland, as well as Glasgow-based broadcaster Kirsty Wark.
Bidders are being briefed by Visit Scotland on how best to appeal to tourists, both from the south of England and overseas.
Whoever wins the franchise will be expected to carve out a distinctive global brand with Caledonian Sleeper promoted as "a passport to Britain's most dramatic scenery" in much the same way as other famous cross-country night trains around the world. In a briefing on the franchise tender yesterday, Transport Scotland executives made clear that they saw no reason why the Caledonian Sleeper - which takes in the landscapes of Ben Nevis and Aviemore on its Highland route - could not acquire the same international renown as services such as the iconic Orient Express.
The successful bidder will also be asked to provide showers for all sleeper passengers at key stations along the route as an alternative to traditional onboard washing facilities, and quality catering services including a restaurant car serving locally sourced or Fair Trade produce.
It will also be expected to offer a wifi service that provides business travellers with an "office on wheels" and leisure passengers the ability to enjoy entertainment and internet access on laptops, tablets and smartphones.