In 2014 I built this Scania R500 and Broshuis extendible trailer. Originally it was laden with a large concrete beam. Hauler Combex also operates these combos to transport large poles to the construction sites. In the Netherlands it is legal to carry them like this, over the cab’s roof to save as much length as possible.
The model is about 6.6 ft long. The trailer is accurate built copy with three steered axles.
The Scania R500 unit is also featured in the book “The Art of LEGO Scale Modeling”.