Beat butter and cream cheese at medium speed with an electric mixer until creamy. Gradually add sugar, beating until light and fluffy. Add eggs, 1 at a time, beating just until blended after each addition.
Combine flour and next 3 ingredients; gradually add to butter mixture, beating at low speed just until blended. Stir in bananas, pecans, and vanilla. Spoon batter into 2 greased and floured 8- x 4-inch loafpans.
Stir together brown sugar, 1/2 cup pecans, 1 tablespoon flour, 1 tablespoon melted butter, and cinnamon. Sprinkle mixture evenly over batter.
Bake at 350° for 1 hour or until a long wooden pick inserted in center comes out clean and sides pull away from pan, shielding with aluminum foil last 15 minutes to prevent browning, if necessary. Cool bread in pans on wire racks 10 minutes. Remove from pans, and cool 30 minutes on wire racks before slicing.