Seriously?
Pep?
Ok, I know you don't want to scratch build this. but for something you will actually be sitting inside of, and holding your own body weight, as well as the padding and all of the structures so it works as a comfortable pod.
You expect pep to work?
Fibreglass may be strong, but no way is it strong enough to hold all of that weight and pressure,you would need a ridiculous amount of fibreglass, which not only would be expensive, it would take AGES to cure, and give off Deadly fumes. Use wood, or something wore reliable, or get an old bed and work around it with cardboard, then fibreglass it and bondo it. That way you're not relying on the fibreglass to hold you up. Plus, I don't know what that is at the top, a window of some sort? Well if it is good luck finding something that will fit. If you scratch build, you can build AROUND a ready made window, so everything fits perfectly.
In my opinion the whole thing is a silly idea. But if you're willing to take this seriously, the last thing you're going to want is a Poisonous, Smelly, Unstable, Tacky gaming pod. If you're going to take this seriously, take our advice, Scratch build. Pep will never work.
EDIT:
Ok, I just researched this thread some more, I understand you cant work with wood, which is fair enough. But I am sure you have friends or family who can help, Anyway, I'm sure you could come up with some good theory, but pep is DEFINITELY not the way to go. Even if you are good at it. I was interested in something like this a long time ago. I was interested in making a Cyro-Tube (The pod Master Chief climbs out of in Halo 1), After research I realized Woodwork, Or metalwork was the way to go, And being Young and still at school. I couldn't really find the kind of equipment and resources for that. So instead of trying pepakura, or Coming up with some crazy theory, I let it go and tried something else. If you cant find a good, Half decent way of making it, then don't make it at all. I'm telling you this for your own good.
I may sound like an Ass to you for saying this stuff. but I'm trying to help, I don't want you to waste a lot of cash and time on something that wont simply work.