I took a 5 x 1 Expedit, put it on its side and installed some 10 inch Molger cabinet legs (they go beyond the back a few inches).
The key to this hack is reinforcement. When I use an Expedit I always put it together with wood glue. Makes a huge difference. The Molger was attached to a piece of scrap wood that I grabbed from As-Is for $1, then attached to the Expedit. I used gorilla glue and bolts. It is sturdy and there is no chance of collapse.