Every once in awhile I run across an old homemade bow that's got crossweave glass laminated on it. They shoot okay.

But if I were going to the trouble to make a form and all that, I'd just go ahead and get bow glass from the sources Lilhunter mentioned. Honestly, it's easier to work with than the crossweave stuff, and coming in with the draw weight you want is a lot more predictable. Looks better, too. It's just better, from any direction you approach it.