Preheat oven to 350° F. Heat 1/4 cup butter and 1 tablespoon rum in a bundt pan, until butter is melted. Sprinkle brown sugar evenly over butter. Arrange bananas evenly over brown sugar sprinkle evenly with pecans.
Beat cake mix, water, 1/2 cup rum, 1/3 cup butter, the cinnamon and eggs in large bowl with electric mixer on low speed 30 seconds beat on medium speed 2 minutes. Pour batter over pecan mixture.
Bake 35 to 40 minutes or until toothpick inserted in center comes out clean. Immediately run knife around side of pan to loosen cake. Turn pan upside down onto heatproof serving plate leave pan over cake 1 minute so topping can drizzle over cake. Cool 30 minutes. Serve warm with freshly whipped cream of vanilla ice cream. Store covered in refrigerator.