I like this idea and I want to make one bigger. (Looking through drawers to find giant tupperware)

The inside of the pink part is sprayed with silver paint. Then I cut a rectangular hole in the bottom, folded back two flaps, and used electrical tape around them to hold a cheapie Hanimex flash in place. The diffuser cuts a couple of stops off the light output, but with faster film I haven’t had a problem. – Link