Preheat oven to 375 degrees. Combine turkey, refried beans, diced tomatoes and sour cream in large bowl. Mix well. Grease 9 x 13 inch glass baking dish. Microwave tortillas for ten seconds each if necessary to allow for pliability when filling. For each tortilla, place 3-4 tablespoons turkey filling in tortilla and four one inch cubes of velveeta. Roll and place in dish seam side down. Repeat for all tortillas. Cut up remaining velveeta cheese (if there is any remaining) and place on top of tortillas. Pour the two cans of enchilada sauce evenly over the top and sprinkle with grated sharp cheddar cheese. Bake uncovered for 45 minutes or until heated through.