Just finished reading Bored of the Rings and wondered if this might be a way to get around copyright? Films have been parodied for ages, mostly comedies, some good (Naked Gun ), some bad (Scary Movie ), so why not a map parody. Even if most players do not get the references, they are still happy to play a new map.
Some ideas thrown out into the open...
Galaxy Quest, so why not a space map with reference to Star Trek.
Austin Powers, evil villains lair with references to Bond.
Barry Trotter, wizards map (harry Potter)
Meet the Spartans gives us an ancient Greece style map.
Westeros gives us Easterios.
Star Wars gives us Car Wars.
Hunger Games gives us Famished.
While some of these examples are not great as in a short time, the original will be forgotten, there is enough classic films/TV shows that are/will be remembered for a very long time.
Before everyone says that major films do not mind these so called good ones, The Asylum film studio does them as well without getting consent.
Transmorphers: Fall of Man
The Terminators
War of the Worlds 2: The Next Wave
30,000 Leagues Under the Sea
Battle of Los Angeles
Very bad films, all of them but Mega Shark versus Giant Octopus is good for a laugh.