There might be i suppose, i could imagine it being some sort of cave the size of the sandbox crypt built into on of the rockfaces. But chances are pretty low, hundreds of easter eggs have been found already and people literally fine comb the game looking for things like that.
It'd be even cooler if fire came out of the monkey's "head." While it would be cool to release more and more parts of Forge World, I'd like to have other areas to work with, mainly for the change of scenery.
Its not exactly a "hidden area" but there is a "frame" outside the map that is not effected by the countdown. The area in this frame is not never ending , though it is REALLLLLLLLLLLY big (not sure if lots of "L"s actually puts any emphasis on my point). There is only one instance in which one can even be close to this "frame" and that is if you pan camera to its maximum speed and then go the furthest you can in a any direction. The "frame" itself is made of nothing (as for as game data goes) so there are no visuals in it. This results in the weird screen-doubles-over itself thing, you get in certain areas in just about every game. The frame acts as a buffer between the playable space and the boundaries of the level code. The idea of it is to keep items from obtaining coordinates that don't exist in the game - which would make the game crash. My suspicion is that all items that enter this "frame" are deleted or are instantly sent back to the center of the map. In halo 3, bungie just made these areas EXTREMELY HUGE, so that even if an item were to be traveling fast enough to break into this "frame", it would never have enough time to reach the boundaries of the level. This may be the same thing for reach but Im not sure. So maybe it is possible to use this space in forge (assuming that you aren't instantly deleted upon entering it) Lolz i made that ENTIRE thing up
I know that there is a place behind the room that I think you can get to with a teleporter. I was searching for maps and someone had uploaded this "secret" area and when I went to check it out, it was pretty lame. It reminded me of the hallway area that was discovered in snowbound on Halo 3.
What he said was actually mostly accurate, though. There is indeed a massive hall-of-mirrors-inducing area outside every level, as each level is loaded into a 100,000x100,000x100,000-unit cube. (You cannot move more than +/-50,000 units in any direction using Halo 3's Pan Cam.) However, you'd die long before you reach it because in all likelihood a hard-coded Hard Safe Area encloses the hard-coded Soft Safe Area that encloses the map.