I am not sure exactly what you are looking for but try http://www.preservationequipment.com/ who have a very good range of storage and preservation materials
Try Bags Unlimited. My wife has used them for quite a while for bags for collectable paperbacks (not custom). Their website doesn't mention custom services, but if you give them a call they might be able to quote something, or give you some leads. The website is www.bagsunlimited.com
Yeah, why not make them yourself. Quite a few plastics can probably be "welded" with a tacking iron. For that matter, those kitchen vacuum-sealer contraptions might do it. I noted some time ago that the edge of a good old iron will firmly seal PrintFile plastic sleeves. Probably a little handheld soldering iron at lowish temp would do it fine, just use a ruler and rule whatever size you want.....
The first one is archival -the second one, I don't know, but they are both good to deal with.
Lynda
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