Ok, I have a problem. I am building a StreetFox and like the seat in the design. Thing is that I want a nice comfortable seat. I stopped at our local craft store and found some really nice green sheets of foam about 5in thick, which IMO would make a very nice seat. Only problem, they want $70 for 1 yard of it!!!!!! So what do you use? Where to do you get? And is it cheaper than that? Also, what do you use to cover it? I was looking at the vinyl, but am unsure of it. The thinner stuff they had looked too wimpy and may ripe after a few uses. The thicker stuff they had looked like it was going to be hard to work with, mainly gettin the wrinkles out. What else is out there that would be good to use to cover the seat? Also, how thick on the plywood? I was thinking 1/2in to 3/4in but not sure.