Preheat oven to 300 degrees F (150 degrees C). Grease four 7x3 inch loaf pans. In a small bowl, stir together 1/4 cup white sugar and 1 teaspoon cinnamon. Dust pans lightly with cinnamon and sugar mixture.
In a large bowl, cream butter substitute and 3 cups sugar. Mix in eggs, mashed bananas, sour cream substitute, vanilla and cinnamon. Mix in salt, baking soda and gluten free flour. Stir in nuts. Divide into prepared pans.
Bake for 1 hour, until a toothpick inserted in center comes out clean.