Combine bread, cranberries, and pecans in a large bowl; toss gently. Combine milk and half and half; pour over bread mixture. Cover and chill 1 hour.
Combine eggs, sugars, rum and vanilla; stir well. Add egg mixture to chilled bread, stirring gently to combine. Pour into a greased 13x9x2 inch baking dish. Bake, uncovered, at 325 degrees for 1 hour or until set and lightly browned. Let cool in pan 5 minutes. Cut into squares; serve warm with maple syrup or sauce of your choice.