I wanted to see if it was possible to build a box like this, with all its tight clearances, using mostly 2x4 material.
I'm happy to say, while difficult, it can be done. The outside of the box are made from run of the mill 2x4's, the bottom/false bottom are 1/4" baltic birch plywood, the compartment is clear pine and the lock spring is made of brass.
MAKE SURE TO WATCH THIS BUILD VIDEO FOR FULL INSTRUCTION!
Plans Available Here - http://dpmakestuff.com/store/
Here is the original build done with hardwood, no instructions.
Step 1: Outside Case Construction
Liberties can be take with the overall design of the box. The secret compartment and mechanism for releasing it are very versatile.
Step 2: Compartment Construction
There are plenty of ways to put the storage holes in the compartment. I used a CNC Router from http://www.inventables.com
Step 3: Assemble the Box and Fit the Liner
The feet and trim are essential to hiding the secret compartment and the compartment is released by manipulating the removeable liner section.
Step 4: Finish the Box
Let nothing hold you back but fear and common sense. I distressed this box to hide the fact that it's made from 2x4. I roughed it up with a chisel and horrible sanding techniques, applied a generous coating of Varathane Wood Stain, the colour was Kona, and polished it with some Briwax to give it a shine.