This may be old news, but I only recently noticed it. The OUTER box that the Pathfinder Battles case incentive "big" miniatures come in (that is, the thick brown cardboard box with the product information, not the thin decorated cardboard box with art) are the perfect width and depth to store Pathfinder Map Packs, both the newer releases that come in little boxes and the older that just came stacked and shrink wrapped.
A fair number of sets fit in one case incentive box with sufficient space for you to lean the cards forward and back so that you can look though them easily without having to take them out of the box.