I had this at a potluck recently and had to get the recipe. It's really good, and the kids were gobbling it up.
 
Hobo Beans 
1/2 cup onions
1 pound cooked ground beef
1/2 pound cooked crumbled bacon
1 can kidney beans, drained
1 can butter beans, drained
1 can baked beans
1 cup ketchup
1 cup brown sugar
1 tablesp prepared mustard
1 tablesp vinegar
 
Mix, cover and bake 45 minutes at 350 degrees.  Uncover and bake 15 minutes more.