Parfleches served mobile Plains people as containers for clothing, food etc and come in many sizes & shapes. Here is an old Cheyenne example of the envelope.
Modern examples are more decorative art...I like fringe and I will try to get Pendleton blanket fabric remnant instead of the very expensive trade wool for the edges. Strips sell on ebay for $5 and should offer enough fabric for this project.
I like the idea of making miniature ones for my dolls so will save all the bits of dog bone rawhide that get trimmed away. This seems like a simple fun project that students can do for little money and yet learn about hidework, some designs & painting techniques and have something unusual to show for the effort. Perhaps some students will want to move on to a larger box: