If I have 30 yards of material 50" wide, and I want to build up 5 layers of 6 yards for each layer of 5oz fabric... any idea how much resin I would need to make this happen?

When the guy said a whole lot, he wasn't kidding. Plus you're talking about a monstrous job. Is the body style you want available in finished form? If so, you might want to look at the cost of the finished one vs your time +cost of resin.

I had a friend who did his floorboard like that years ago, and I thought I remembered it taking a few gallons, but I wasn't sure. So I contacted a local supply shop in Cleveland, and the guy did the math and said the following: The resin will pour out in a thickness between 1/32 and 1/16 of an inch. At 1/16 of an inch, it will take three gallons per layer for a total of 15 gallons for the project. And then don't forget that you will need to cover the whole shell in gell coat for your finish layer. I don't know how much gell coat it will take. I forgot to ask the guy about that stuff. But I know from hot tubs, that it's the stuff that gives the final layer. For something that size though, it could take a couple of gallons is my guess, because it goes on really thick.

There is a website where you can get 5 gallons at a time, you might want to look into that. Ill see if I can find it. http://www.selectproducts.com/