[Snowtractor]

...car mufflers indeed. There are such a variety of agriculture mufflers as to stagger the imagination. I walked in to a Aklands a few years back and got 2 mufflers EXACT length and diameter, very heavy gauge and for dirt cheap. I saw some in Princess auto ,in april, that look to be right for 20 bucks a piece.
Don't limit your thinking to "automotive", heavier industry has been repairing short run specialty equipment for years. This means they are more set up to build you what you want and quite often cheaper than you think. Because they have the equipment the can do the job faster, often, to significant savings even though shop hourly rates may be higher. As example there are the mufflers and brake shoe relining and Nigel getting his carrier road wheel rerubbered at a forklift tire relining shop ..for dirt cheap.
Sean