Also you can find the Psycho house at this link. I know it isn't Sci/Fi, but it is a nice Victorian house that could be used in a diorama. http://www.haunteddimensions.raykeim.com/
A good haunted house, again Victorian, that could be cleaned up/re-painted to look new is at: http://ravensblight.com/papertoys.html (this site has two, one rather simple, and one that is better).
One more paper house that could be used in a diorama is the house from Up, which you can find here (again, repaint it to look more normal). http://paper-replika.com/
I am sorry this is not a lot, but maybe it will be useful.