Combine one 10-ounce bag shaved Brussels sprouts, 1 cup halved green grapes and 1/2 cup chopped toasted pecans in a large bowl. Cook 2 chopped slices thick-cut bacon in a skillet with olive oil until crisp, about 5 minutes. Add 1 sliced shallot and cook until softened, 3 minutes. Stir in 3 tablespoons red wine vinegar and 2 teaspoons Dijon mustard. Pour over the Brussels sprouts; season with salt and pepper and toss.