Season pork loin with salt and pepper. Roast pork at 350° F for 1 hour, cool completely.
Trim crust from bread. Cut loaf into 1/2" slices. Brush with 1/2 ounce melted butter on each side. Grill bread until lightly browned on both sides.
Slice roast pork to desired thickness.
Arrange 3 basil leaves on each slice of grilled bread. Next, add 3 slices of roast pork. Then add 2 slices of tomatoes, and top each with 2 slices of blue cheese. To serve, place sandwiches in 350° F oven for 15 minutes. Remove from oven. Cut each sandwich diagonally.