+1. I was just about to post this same suggestion for semi hard organizers. If things are inexpensive, figure they are one to three trip items and then replace when they get tattered.

Think outside the "travel goods" box. Wander through your megastore mart plastic box aisle or home improvement mart tool box area for boxes and organizers. Lowes has some canvas zippered bags in various sizes in the tool area that are excellent lightweight tough organizers.

For the OPs description of a semi hard letter size by 3 inch container, go to a large office mart and look at expanding file pockets with folding cover. Some are tyvek plastic and tough as heck with little weight. ^ Great organizers. The brown ones are also tough enough for several trips.

add regarding non traditional packing cases: I have a NW J amenity kit zipper case that is just the right size to hold my laptop charger and a travel mouse.

I have also looked at zippered book covers when looking for semi hard travel cases. Sometimes called bible covers.

Office supplies carry the zippered notebook three ring binders which I looked at but they are just a little toooo big.

Although pricy, I did find a leather Roladex brand zipper case at the office supply store which is about 11 x 8 x 2 inches and a great packing aid. Drill out the rivets to remove the ring binder and it is a great electronic packing case.