Mix flour, cornmeal, sugar and salt in the bowl of a food processor. Add butter and pulse until incorporated. Add water, 1 tablespoon at a time while pulsing, until ball forms. Remove and wrap with plastic wrap. Chill at least 30 minutes.
Roll dough out on a lightly floured surface with a lightly floured rolling pin into a 14-inch diameter round. Fit into a 9-inch pie pan, and crimp excess dough around the edges of the pan. Chill at least 15 minutes.
Preheat oven to 350F.
To prepare the filling, combine 8 ounces cream cheese, sugar, eggs, half-and-half and flour in a bowl. Beat with an electric mixer on medium speed until smooth. Remove 1/3 cup of the mixture and transfer to a separate bowl; reserve. Add pumpkin, cinnamon, ginger, allspice, salt and nutmeg to the egg mixture in the mixing bowl; beat until smooth.
To the reserved egg mixture, beat in remaining 4 ounces cream cheese and maple syrup.
Pour pumpkin mixture into the pie crust. Spoon little dollops of the maple mixture all over the top and gently swirl it through (using a fork handle, or a chopstick) the filling.
Bake on a baking sheet, 50 to 60 minutes, until filling is just set. Remove from oven and let cool on a wire rack 1 hour. Transfer to refrigerator and chill at least 3 hours before serving.