The Danish company MTDK has supplied 5 trailers with sliding tarp systems to DHL. 

By supplying a custom built system, DHL can position a 40ft container on the trailer platform prior to sliding the tilt over the container and then tensioning it.  The container is always covered and the DHL logo is always visible.  After unloading the container, the trailer can be used for general cargo on the return leg. The trailers can also be extended by 2.00 metres when transporting 15.00m long tubes. That is flexibility!