Cut each roll in half; roll each into an oblong shape. Arrange in two greased 13-in. x 9-in. baking pans. Cover and let rise in a warm place until doubled, about 30 minutes.
In a small bowl, whisk egg and water; brush over rolls. Sprinkle a third of the buns with poppy seeds, another third with caraway seeds and the remaining buns with cheese. Bake at 350° for 14-16 minutes or until golden brown. Remove to wire racks to cool.
Meanwhile, place hot dogs in a 15-in. x 10-in. x 1-in. baking pan. Bake at 350° for 12-14 minutes or until heated through.
For Chicago Dogs: Place a hot dog in a poppy seed bun. Top with a teaspoonful of mustard, relish, onion and tomato. Repeat. Top each with pickles.
For Bavarian Dogs: In a small bowl, combine the sauerkraut, apple, onion and celery. Place a hot dog in each caraway seed bun; top with sauerkraut mixture.
For Chihuahua Dogs: In a small bowl, combine the salsa, pineapple, cilantro, jalapeno and lime peel. Place a hot dog in each cheese bun; top with salsa mixture. Yield: 3-1/2 dozen.