In a large mixing bowl, combine cake mix and pumpkin. Stir until completely blended (the mixture will remain very thick). Spread batter into a large baking pan (about 9 X 13 ) sprayed with nonstick spray, and set aside.
Combine softened cream cheese with Splenda, Coffee-mate mixture, and vanilla extract. Using a whisk, mix vigorously until completely blended, smooth and lump-free. Spoon cheesecake mixture over the brownie batter, and use a knife to swirl it inches (Don't worry if your swirl isn't perfect - your brownies will taste delicious no matter what!) Place pan in the oven, and bake for 20 - 25 minutes.