I had to start with a Warboss. I bashed this guy together:
It's a stock Warbike, with old Imperial tank wheels and track links overlaid on the bike rear wheel.
The Engine is a chopped up heavy flamer, stacked on another pair of bolters with lots of extra plasticard.
The boss's power klaw is an old Chaos Marine Heavy Bolter and another Orky Bolter, with more plasticard:
More to come...