Arrange bread slices on a lightly greased baking sheet. Broil 6 inches from heat for 3 to 4 minutes.
Melt butter in a saucepan over low heat; add flour, and cook, whisking constantly, until smooth. Gradually whisk in milk; cook over medium heat, whisking constantly, until mixture is thickened and bubbly. Add Cheddar cheese, whisking until cheese melts. Stir in diced turkey, salt, and ground red pepper.
Top bread evenly with warm cheese-turkey mixture. Sprinkle evenly with Parmesan cheese and half of bacon.
Bake at 500° for 2 minutes or until Parmesan is melted. Top with tomato slices, and sprinkle evenly with remaining bacon.
To make ahead: Prepare the cheese-turkey mixture, cook the bacon, and grate the Parmesan the day before the party. To reheat cheese mixture, place pan over low heat, stirring constantly, until smooth and warm. Assemble and proceed as directed.