Well, put 4 butts in there, 7.5 lbs each, cooked down about 15 lbs of meat and at 1/4 lb per sandwich, that's 60.
We always advise asking us for recommendations, based on the amount of what you're wanting to cook. You'll be able to cook plenty, you just may have to cook some in advance, say big cuts like briskets/butts and hold those while you finish smaller stuff; ribs or chicken.