I wanted to test the dimensions before committing this design to precious ash, or maybe fir, or pine, or even cherry or walnut; I also have a lot of maple on hand. I used old cedar fence slats and scrap ply for the mockup. So far the dimensions (5x8x30ish) seem to work, I may try adding dividers before placing many more tools.
This particular type of cedar (I think it's western red - used extensively in Frank Lloyd Wright's Gordon House) dents incredibly easily so the french marks aren't really my fault. I think the exposed edge plywood bottom accents the piece nicely.