Little shelves to hold 20 small containers http://www.thingiverse.com/thing:12177
(16 of 30mm and 4 of 40mm height)
The main picture shows the model I made for myself (3mm plywood and 5mm acrylic and a little oversized with 30 containers), the model here is intended to be made in 5mm material (e.g. 5mm MDF).
1) Put together the sides and the shelves
2) Then the bottom and upper plate
3) add the long parts of the back
4) fix every mortise and tenon with a little peg
5) Print small containers with your RepRap and organize your stuff :)