charlieb wrote:

I like the idea of "french cleats" for hanging stuff off the wall.
I made wooden ones to hang the two wall hanging tool cabinets
in the shop. But for my first "house" furniture, I don't want
to screw two halves of a ripped 2x4 into the studs on the
wall and waste hall space to accomodate them in the back
of the shelves.

Not what you are looking for, but how about making just the shelf in front
of the cleat narrow enough to accomodate a wooden cleat? A bit more
complicated, perhaps, but less expensive.