I bought two "universal" Geneva tool boxes (http://www.genevamfg.com/shop/category.aspx?catid=19)that describe as follows: 6-ft bed w/1 divider, All Steel Powder-Coated Sidebed III Storage Box Part #460011. All that means that they are designed to fit a pickup behind the cab with a six foot bed. I installed them right on top the the sewer hose carrier/bumper. These are about 18" wide and very high quality/water proof. They have the same tool box for a 8' bed, meaning it will be a little longer. The only down side is the cost as they were about $300.00 each. Yes, kind of ridiculous, but I was pushed for time, short on space. I have had more people compliment me on those little boxes than I can remember. They look like they belong on the trailer.