In a small bowl, dissolve yeast in warm water and set aside. In a large bowl mix milk, 1/4 cup sugar, 1/3 cup melted butter or shortening, salt and eggs. Add two cups of flour and mix until smooth. Add yeast mixture. Mix in remaining flour until dough is easy to handle. Knead dough on lightly floured surface for 5-10 minutes. Place in well-greased bowl and let rise until doubled, usually 1 - 1 1/2 hours.
When doubled, punch down dough. Roll out on flour surface into a 15x9 inch rectangle. Spread melted butter all over dough. Mix 3/4 cup sugar and cinnamon and sprinkle over buttered dough. Sprinkle with walnuts, pecans, or raisins if desired. Beginning at 15 inch side role up dough and pinch edge together to seal. Cut into 12-15 slices. Coat bottom of baking pan with butter and sprinkle with sugar. Place cinnamon roll slices close together in the pan and let rise until dough is doubled, about 45 minutes. Bake at 350° for about 25-30 minutes or until nicely browned.
Meanwhile, mix 4 tablespoons butter, powdered sugar and vanilla. Add hot water 1 tablespoon at a time until the glaze reaches desired consistency. Spread over slightly cooled rolls.