Yeah, sometimes Oil Rigs seems a bit too big when I end up getting lost on either end while inside the superstructure trying to find my way back up to the surface.

There's also DC's giant Nimitz class carrier on the same map, which is big enough to have a good firefight on as well.
GC ISD Judicator is another fairly large interior map. It's pretty neat looking when you get to the bridge and can look out to see a bunch of Rebel ships hovering around it.
Just imagine it though....a Reichstag with up to 64 people running around inside. There'll be so many grenades flying.