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