I've just completed a custom general purpose fire brigade tipper on a Peterkin Unimog chassis. I had a chassis and cab spare from an aborted emergency tender custom and decided to hang on to it with the view to building a custom flatbed truck. I had actually built the flatbed when I came across a new Peterkin set on the construction theme. This had in it a Unimog tipper in "kommunal" orange and a G Class also in orange, as well as some figures and signs. I decided to buy the set, keep the G Class and the Uninmog, passing the rest on to a friend in the village who works for a local playgroup. The Unimog I then used to supply tipper body for my spare fire engine chassis and here are the results. The load are 1:35 sacks from Britains farm series but here representing sandbags for flood defences.
The tipper mechanism operates with quite a fancy gear mechanism - see fourth photo