I bought some raincoat material for a steal (half off of half off with another 10% off on top of that - they nearly paid me to take the stuff) and I've been trying to figure out if it would work for a picnic quilt too - I'm watching this thread closely!
Vinyl might be just too heavy/stiff to make a good quilt; depends on what gague you get, I suppose. I like the raincoat material because it is very flexible and thin. And it's black, so it'll hide any spots it does pick up. But I was wondering if quilting holes would let in moisture too, just as somone asked. Somehow it works okay on my coat, though...maybe just use a fine needle and keep the stitches small & tight??