Preheat oven to 350. For crust: in a large bowl, beat the butter with an electric mixer on medium to high speed for 30 seconds. Add sugar and vanilla. Beat until well combined, scraping bowl occasionally. Beat in the flour, cinnamon, and salt. Press crust mixture evenly into the bottom of an ungreased 9 x 13" baking pan. Bake in preheated oven for 15 to 20 minutes or until light brown. Cool completely in pan on a wire rack.
For Filling: in another large bowl, beat butter on med. to high speed for 30 seconds. Add brown sugar, baking soda, and salt. Beat until combined, scraping bowl occasionally. Add eggs, bananas, rum, and vanilla. Beat until combined. Beat in the flour. Spread filling over cooled crust in pan.
Bake in the preheated oven for 40 to 45 minutes or until a wooden toothpick inserted near the center comes out clean. Cool completely in pan on a wire rack. Frost uncut bars with Cinnamon Rum Frosting. Cut into bars.
CINNAMON RUM FROSTING: In a large bowl, combine butter and cream cheese. Beat until combined and fluffy. Gradually beat in powdered sugar and cinnamon. Beat in vanilla and enough rum to make a frosting of spreading consistency.