Arrange ½ of the bread cubes in a greased 9 x 13 pan.Sprinkle cream cheese cubes and blueberries evenly over the bread cubes.Top and evenly sprinkle with remaining bread cubes.Mix together eggs, syrup, milk and vanilla in a large bowl.Pour over bread cubes. Press the bread cubes slightly down to absorb the milk/egg mixture. Cover pan with foil. Let chill in refrigerator overnight.Bake covered with foil at 350 degrees for 30 minutes. Remove the foil and bake for another 30 minutes or until fluffy and golden. Top with blueberry syrup.In a medium saucepan over medium heat, cook water, sugar, and cornstarch until thickened. Stir in blueberries and simmer for 10 minutes. Add butter and stir until melted. Serve over the french toast.