Master MOCer Thirdwigg, who has packed it not just with working Technic functions, but also an array of attachments and tools in much the same way as the real thing would be.
Working steering, pendular suspension, a piston engine, and a tipping cab all feature, with a folding crane, three-way tipping bed, street sweeper, and snow plough all attachable via the adjustable hitches and mounting points.
Flickr album of the same name and at the Eurobricks forum, where full imagery and yes – building instructions are available too!