In large microwaveable bowl, mix cereals and pumpkin seeds. Line cookie sheet with waxed paper or foil. In small bowl, mix brown sugar, pumpkin and pumpkin pie spice; set aside.
In 2-cup microwaveable measure, microwave butter on High about 30 seconds or until melted. Add pumpkin mixture; microwave 30 seconds to 1 minute, or until boiling. Stir in vanilla.
Pour pumpkin-butter mixture over cereal and seeds, stirring until evenly coated. Microwave uncovered on High 5 minutes or until mixture begins to brown, stirring every minute. Spread on waxed paper to cool.
While mix is cooling, melt white chocolate in microwave on High 30 seconds; stir in softened cream cheese. Drizzle over top of mix; refrigerate 5 minutes or until set. Store in airtight container in refrigerator.