The Solution: A do-it-yourself project!
Materials needed: A large board for a work surface, a long narrow board to be used as a straight edge, some 8½" x 11" sheets ( I just used the basic ones from Staples), and...
...a wood-burning tool.
The 8½" x 11" sheets that I have are pretty thin. I figured that they would melt pretty easily. I thought that if I used a wood burning tool and scored a line using a straight edge, it would melt the sheet along the score to make a pocket.
I used the dull side of the tool and followed the straight edge. Too fast and it didn't melt enough. Too slow and it cut instead of melted. Just right and I have pockets to slip the pictures into that won't let the pictures do much sliding around.
You could probably using this technique to make any sized custom pocket for those odd shaped items.