Cheap/dimensional is an oxymoron in my book. PVC all the way then, cheap means they get a splice seam since you won't be able to get PVC larger than a 5'x10' sheet. If it has to be seamless, then you have some work in front of you filling as said earlier. I would whip out something like the one shown for no less than $2500. That's what its worth at a minimum. Although there are plenty who would do it for less. I like profit. Just because they want cheap does not mean you should do it for cheap.