I took 2 pieces of 3/4 PVC glued together to give me a 1 1/2 thickness. Then purchased some clear plastic tubes. Two sizes 3 inch x 1/2 and 2 inch x 5/8. These are large enough to hold most bits except for extended length. You could probably find longer tubes if needed. The square holes are also large enough to hold the square tube a lot of the bits from various vendors come with.
Then drilled the PVC to hold the various sizes I have. Drill depth is about 1 inch using a 1/4 end mill. Used small clear return address labels to mark all the tubes and the rows on the board.
.c2d File is attached.
End Mill Case - New.c2d (561.9 KB)