U know i wish i did, maybe this photo will help some, tho it's hard to see behind the kid in the foreground--
Len-- i just buy mine at KWal-Mart, and i think they're called the Hot Seat, or something like that, i got a bunch of 'em awhile back for $4 after hunting season. All these are are just the soft-sided stadium seats. Sometimes the stitching rips out, and they have to be resewn, and if u push too hard on the back it'll rip too at the seams unless reinforced, but for $4-10 i don't really care. Mike (Yotefever) put camo fleece on his, and sprayed the seat part wth some kinda' goo that keeps u from slipping around on it--excellent idea.
U really do have to sew the female end of the snap closer to the seat itself tho. It won't work well unless u do this little modification.