I have a spare Griffindor tower from the classic Harry Potter lego set 4757 from 2004, which can be added to the original set ( and changed into a Slytherin tower with green tiles instead of red) or to any other Harry Potter lego Hogwarts castle! It has 2 of the 4 Poster beds from the Gryffindor boys common room, which is a great addition for any Harry potter Hogwarts castle! No minifigures you get what you see, the flag is light gray instead of dark bluish gray.

You can get the instructions of this tower via lego.com for set 4757 pages 73 - 91