Well, I consider myself an expert on everything Metal Gear. I have over 50 Metal Gear games, for every system, language, region code, whatever. In fact, I am the second largest collector of Metal Gear merchandise in the world. I have almost $8000 invested in Metal Gear stuff right now. Point is, I know Metal Gear. And being an airsofter, Snake's sneaking suits were probably the first thing I wanted to make. And I can tell you right now, if you want it to look good, it will be impossible. Simple as that. The fact is, you cant buy half of that stuff anywhere. Its a video game, its made up. The only option is to make it. But that will be very hard, just look at the links posted above. They obviously spent a lot of time making those, and they still look like horrible shit. To come up with something even remotely close to the vest would be incredibly difficult. Plus I'm sure you dont have the muscles for it. My advice is dont waste your time. If you make a half ass attempt, you'll end up looking like this fucking douche.
http://www.candyhearts.net/images/Cospics/snake4.jpg
Even if you try really, really hard, its still going to look like shit. And I swear to god, if you do make it, and use it for cosplay, I'll hunt you down and sodomize you with an object so large that you'll make goatse seem water tight.