Spray the inside of a 6 quart slow cooker with cooking spray. Set aside.
In a large mixing bowl, mix together the beef, sausage, breadcrumbs, buttermilk, onion, eggs, parsley, worcestershire, seasoned salt and garlic. Mix until ingredients are evenly distributed.
Roll into 1-inch balls.. Arrange in the slow cooker.
In a small bowl whisk together the barbecue, chili sauce, pineapple preserves, Dijon, garlic salt, onion powder, pepper flakes, cumin and chipotle powder. Mix well, then pour evenly over meatballs.
Cover and cook on low for 4-6 hours or until meatballs are cooked through and no pink remains. Use a large spoon to skim any fat from the top at the end of cooking.
Use tomato paste to thicken sauce, if desired. Gently stir meatballs to coat with sauce. Keep warm until serving.