That's exactly what I intend to do.
There're many fleets in the world composed by vessels already in the game -or slight variations- that can make for lots of scenarios. Since the big exporters are in the game, the importers can be also.
Curiously I can't make my country's navy, Spain, since we make our own boats. Usually based on other countries' technologies (USA, France, Germany) but own design, own shipbuilding. For those of you who haven't been introduced to it, the Spanish Navy is quite interesting. But I'd have to create everything from scratch, and that takes a lot of time that I don't own now.
Best regards from the warm waters of the Mediterranean,