I have recently become a Unique Dog box dealer, they offer a varity of styles and sizes. If you don't find the size you want they can custom make it. You can check them out at www.uniquetruckaccessories.com.
Give me a call if you find something you or if you have any questions. I can get you a great price,and can also have them shipped to most locations. Thanks Jerrad 563-219-0101