Stiffened poly outer sleeves?

I ordered some laserdiscs from some place in the Netherlands. They came with some stiffened poly outer sleeves. I have asked where the seller got them and he said someone he has forgotten at a fair in Holland. Well,

I was wondering if anyone here knows where I might fight something like this? I have checked Bags Unlimited and Vinyl Revival and all they have are the floppy comic book/magazine style bags.