Years ago, I tried to sell some tool boxes at the local hardware store. I sold some but not many. I used the left overs for my own tool boxes. I have one with all my layout tools in it, and one with a good lot of hand tools.

The basic design is like this:



And can be about any width and length you need.

Here is a shot of mine with some tools in it:



I have a slot on the side for my framing square, and several slots for standing up my chisels, corner chisel, and combination square.