on an old work truck, we used to have a removable ladder rack
It came with base plates that bolted to the sides of the bed, and then when we needed to haul something, we'd slide the legs of the two sections (front of the bed and back of the bed) into the premounted brackets, slide in some pins, and go. this would probably work real well with some kayaks, andwhen we were storing the rack pieces, they didn't take more than 6" deep of space, so we'd keep them behind some shelves in the warehouse
