I just found about this place. It is in an unmarked old schoolhouse.
Nyholms 12133 Spring street mt. Pleasant, wi. 262-886-9543
Family run since the 1940's. Very nice owner that I dealt with. He claims to have 50 varieties of popcorn, he buys in bulk and sells in 1/2 and one gallon sizes if you want. I picked up a gallon of a small white popcorn that goes for $5 for four ounces in the grocery for $10 a gallon.
I will say that his wife was dealing with a commercial customer that had driven down from "up Nort" and filled up his truck due to the prices.
There is not much to see - not a real store front as opposed to a cubbyhole and a storeroom.
But if you know what you want, or samples to pop of different flavors, gallons of topping oil or gallons of coconut oil, please give them a call.