In a saucepan over medium heat, combine the sugar and corn syrup, and bring to a rolling boil. Remove from heat, and stir in peanut butter. Mix in the rice cereal until evenly coated. Press the mixture into the prepared pan.
In a glass bowl in the microwave, melt the chocolate and butterscotch chips, stirring occasionally until smooth and well blended. Spread over the top of the bars. Chill until set, then cut into bars.