Lightly grease a 9x13 inch baking dish. Arrange half the bread cubes in the dish, top with cream cheese cubes. Sprinkle 1 cup blueberries over the cream cheese, and top with remaining bread cubes.
In a large bowl, mix the eggs, milk, vanilla extract and syrup. Pour over the bread cubes. Cover and refrigerate overnight.
Remove from the refrigerator about 30 minutes before baking. Preheat oven to 350 degrees.
Cover and bake 30 minutes. Uncover and continue baking 25 to 30 minutes until center is firm and surface is lightly browned.
In a medium saucepan, mix the sugar, cornstarch and water. Bring to a boil. Stirring constantly, cook 3 to 4 minutes. Mix the remaining 1 cup blueberries. Reduce heat and simmer 10 minutes until the blueberries burst. Stir in the butter, and pour over the baked French Toast.