When I asked the butcher at my local Kroger, I found out the Butterball ones come 8 to a case, and they were happy to order me as many cases as I'd care to pay for and pick up.
I'd say hit up the meat counter at your local grocery and see if they'll order you cases.
The Butterball bone-in breasts can be smoked (and come out really well) exactly as they come. They're not too salty, but the brine they come in keeps them super moist at BBQ temps. If I needed to smoke like 100 of them, that's what I'd use.