Grease a 13×9-inch pan or two 9-inch round cake pans with shortening or cooking spray.
In a small bowl, mix warm water and yeast; let stand for 5 minutes.
In a large bowl, mix the cake mix and 2 cups of flour. Add the water-yeast mixture and stir with a wooden spoon until dough forms. Gradually add the remaining flour, 1/4 cup at a time, stirring between each addition until the dough comes together in a ball. You may not need all of the flour. Cover with plastic wrap and let rise in a warm place until doubled in size, about 1 hour.
Gently punch down the dough and reshape it into a ball. On a lightly floured surface, roll the dough into a large rectangle about 1/4 inch thick.
Brush the dough with melted butter and sprinkle evenly with cinnamon, brown sugar, and rainbow sprinkles. Starting with one long end, tightly roll the dough into a log. Cut the log into 12 rolls.
Place the rolls in the prepared pan(s), cover with plastic wrap, and let rise for another 30 minutes while preheating the oven to 375°F (190°C).
Bake for 20-22 minutes in a 13×9-inch pan or 12-15 minutes in the 9-inch round pans, or until the rolls are golden brown.
Cool for 5 minutes, then spread the rolls with the whipped cream cheese frosting. Garnish with additional candy sprinkles. Serve warm or at room temperature.