Kevin, I use what I believe you are looking for:
The first batch I received from Paddy and the second batch, I found either on ebay or at Office Depot (sorry can't remember)...
As the images show, there are 2 pockets. The pockets are vertical and can easily handle most (if not all) folded maps whether tri-fold, bi-fold or multi-fold... I use mine for maps and large ink blotters, in the 3 ring binders that I store my "excess" items....
The brand name on the sleeves is: "Collector Safe" and they are marked "Premium"....