Has anyone built a platform in the back of the cab for their furry friends? I just ordered a 5-step "dog ladder" so that my 9-year old Yellow Lab can climb in more easily and to protect hips and joints. I am thinking of building a platform in the back that would be level with the rear seats (the 60 of the 60/40 foldup) and then put one the above listed blankets or hammock on top.