This must be one of the the nicest Lego models I've seen in Blender. And its timing is great, with all the current attention for the Lego movie ;-)
The old Lego Technic Bulldozer was published in 1993 under the set number 856. It has a total of 172 pieces of Lego, 46 individual Lego parts+2 rubber bands.
Rendered in blender cycles: 1000 samples
Rendering time: 1 hour, 50 min and 58 sec
Post pro: blender node editor
Comments/criticism are appreciated