The Cimerorans are unlockable, and the Cimeroran caves, but I don't believe there are any Cimeroran outdoor maps available in the Architect.
Obligatory word of warning warning: While you might be able to get away with a similar story on the grounds that it's based on real historical events, the arc is likely to get yanked if it comes too close to the movie or original comic book.
Any arc can be hero and villian. You just have to go to the RWZ to team together.
Cims are available content to unlock.
And no, I don't recall any outdoor Cim maps either.
I'm wanting to make a CoHaV (City of Heroes and Villains) version of the movie "The 300" so I' wondering if the Cimeroa landscape and the romans are possible to get to use in a created mission?