Preheat oven to 350 degrees F.
In large bowl, mix together beans, pineapple, molasses, BBQ sauce, mustard, 1/4 of the bacon, and 1/4 of the onions. Add some salt and pepper, to taste. Pour beans in 9- by 13-inch casserole dish and sprinkle remaining crushed onions and bacon on top. Cook in oven for 1 hour or until beans brown and bubble. Serve warm.