Thick slab of glass

Anyone ever saw a shop that sells, say, a 12" x 12" x 1" thick glass plate/slab (must be clear/transparent). I only see stuff at less than half an inch thick. Thanks.

Ask if the shops selling the 1/2" thick slabs can help you locate a factory that can make you a 1" think slab. I have a friend of a friend that has a glass factory, if you get stuck after asking your local glassman, then send me a PM and I will take the time to ask for you.