I ordered this kit of reamer (from 2 to 10 mm) on the web and they come without a case, so I decided to design my own.

This is a two pieces case with snap closure mechanism. The hinges are made by using a couple of M3x16 hex socket cup screw directly fastened in the plastic.

I do not know if reamer size has a standard or if their length is variable, by the way you can download the solidworks file and modify it to fit your kit