Found this - knew there was another one but don't think this is the factory one. So there are at least two of them. Rear set up is different on each. One is based on the Pinzgauer setup and this on is based on the standard Haflinger setup.
http://www.zwischengas.com/de/FT/fahrze ... Hufen.html
There is a bit of video of it in action as well if you want:
https://www.youtube.com/watch?v=jlxOZN2U51Y
John
edited title