Place bacon in a large, deep skillet. Cook over medium-high heat until evenly brown. Drain, crumble, and set aside.
Saute onion in bacon fat; add the brown sugar, mustard, garlic powder, salt and vinegar. Cook covered on low heat 20 minutes.
In a four quart baking dish, combine the bacon, onion mixture, butter beans, lima beans, kidney beans, garbanzo beans and baked beans. Mix well, and bake covered for 1 1/2 hours. Uncover and bake 30 to 45 minutes longer.
