Hypalon can be had in 56" // 57" widths all over the web. Running at about $22 ~ $27 a lineal foot, it gets expensive really fast! Any color you like though! I don't know of the valves you speak of, but it would make sense that they are glued on valve-boots, then the valve attaches to that.

the valves depend upon what manufacturer you are working on. Some like Achilles are 2 part and are glued from the inside.