Cut bread into 24 (3/4-inch-thick) diagonal slices.
Whisk together eggs and next 5 ingredients until well blended.
Place bread slices in a 13- x 9-inch baking dish; pour egg mixture evenly over slices. Let stand 30 minutes or until liquid is absorbed.
Remove bread slices from egg mixture, letting excess drip off. Cook bread slices, in batches, in a lightly greased nonstick skillet or griddle over medium-high heat 2 minutes on each side or until golden.
Place bread slices on baking sheets; keep warm in a 200° oven.
Cook Champagne in a large saucepan over high heat until reduced by half. Gradually stir in syrup; cook over low heat until blended and warm.
Arrange bread slices on serving plates; top with raspberries, blueberries and, if desired, cream cheese. Drizzle evenly with syrup mixture. Garnish, if desired.