The MSX data tapes from GZ and TPP are likely the only things left that could be a really huge secret. That Camp Omega stuff is probably lost forever. It's amazing that we were even shown the Episode 51 stuff. Wonder how that got approved.
Supposedly the Camp Omega stuff is still in the data files, but that is going from a random internet message board posting. I'm really hoping the MSX tapes pan out to be something mind blowing though. The whole Episode 51 being cut is supremely disappointing, you get that big scene where Eli jacks the Metal Gear and vanishes but then there's no pay-off to it.
Yea I wouldn't be surprised if I found it during one of the main ops or side ops. It seemed like it was supposed to be the most powerful scene besides hallway scene and subsequent scene with the ashes.
Yes
I came across it during one of the Mine Disposal side-ops. You can see the bodies laying on the side of the road burning.