the blunderbuss was indeed a flame template attack in 5th edition as well. The War Wagon was the only way to get one on the field, just as the STank varient is the only way to get one in 6th edition.
scary thing is, I went back and did some adding, this would be a ~500 point Skirmish battle at least.
ah well, I had fun writing it, glad folks enjoyed reading it!