Small Room Solutions

We live in a really small apartment in the city and while I know that if we moved out of the city we could get a bigger place, I am not willing to make that sacrifice. In the meantime, I have to come up with a solution for my 2 growing children to be able to share a room without killing each other as they fight for space. I have thought about buying bunk beds for them because it would be great to save space in their room but I am wondering if I am just not adding another argument to their repertoire. Are they now going to argue about who sleeps on which mattress?