Dice unpeeled red potatoes into 1/2-inch cubes. Place in a large Dutch oven, cover with water and bring to a boil. Let boil for 10 minutes or until 3/4 cooked.
In a separate large Dutch oven, combine melted margarine and flour, mixing until smooth. Place over low heat and gradually add half-and-half, stirring constantly. Continue to stir until smooth and liquid begins to thicken.
Add melted Velveeta. Stir well. Drain potatoes and add to cream mixture. Stir in pepper, garlic powder and hot pepper sauce. Cover and cook over low heat for 30 minutes, stirring occasionally.
Place soup into individual serving bowls and top with crumbled bacon, shredded cheese, chives and parsley.