If you haven't already been shopping, you are going to have a tough time. I had a tough time finding one I like for my regular bed. I would recommend taking your measurements and going to Lowes, Home Depot, and Tractor Supply (or comparable store) and see what your options are (in stock or special order.) If no luck there, try a specialized truck store or the internet. Lowes had a narrow box that might work (it was in the $150 range.) Best of luck.