In all my life I have never heard anyone use starting fires as an excuse to put a stack on a truck.
I have also only seen one fire ever caused by an exhaust, and that was a beat up Thunderbird kids used to field hop with that still had a cat on it and was bottomed in dry grass and left running for 20 minutes.
We are a family of dairy farmers...
If you like the looks, and want the sound, just say so. If you need an excuse, I can't really help you.
The depth of the sound will be directly related to the diameter of the pipes. If you want it in any way deep, you need 3" pipes at a minimum. If you want that redneck "rap/pop" to the exhaust... you use smaller pipes. The dual 2" with unequal sized cherry bombs were a favorite for that in the old days. Personally, it was even worse than the annoying "Flowmaster drone" the Mustangs used to have. (The resonance was horrid)
If you want a stack, with a small amount of muffling, just run 2 1/2"-3" pipes with some cherry bombs or "Bullet" mufflers and make it taller than the cab by a couple of feet and turn outs pointed back or out.
It's not going to sound like a Cummins, but it's what I think you're after.