The camera wouldn't be the hard part. In order for your idea to work, it would require creating models that have pathing. That would eliminate the ability to create twists and loops in the roller coaster. Everyone would have the same limited choices of models to use, which would make it blunt. And I don't think there is a way to change the height of terrain in game, which might be essential if you were to leave the players with any sort of creativity. That's just the multiplayer side to it.
A cinematic would be heaps easier to do, but I don't think the outcome would be as nice considering you would have to create a load of models to actually make it look like a roller coaster ride.
In conclusion, the possibility might exist to create such a map, but the complexity wouldn't be worth it. There are so many better maps to make that would require 1/1000th of the time to make the game of which you speak.