This is inspired by http://www.thingiverse.com/thing:422819 from pegasocube.

I liked the Idea but the hex holes were too close to each other for me, so I made one that I could tweak to fit my need. You can adjust several things, like the number of hex bits it can hold, the height, etc. I also made a lid to go with it.

I've added a couple improvement after having printed mine, I've added holes in the bottom to help removing bits if they get stuck. And I've added holes on the lid to make it easier to remove as well.

I suggest to print one with 5mm height and 4 holes in it to test and adjust the width of the hex shape, ideally it should be slightly tight to hold the bits whilst easy to remove.