Perhaps not quite an unknown practice, this is sometimes referred to as 'Chopping" for obvious reasons! We have seen a number of these 'new creations' down through the years and would encourage any of you collectors out there to present a photo of any that you think are worth while.
They are in a similar class as the 'Superised Fun Ho!' and are often made up of old parts which are otherwise wasted ...Barry
Fun Ho! 522 - Jumbo Articulated Truck