Lots of small space ideas. Sliding Walls in Living Room. You can simply slide it open to create a larger, open space for entertaining when you want.
Sliding door into bathroom. Doesn't have to be barn door look but I like the sliding door idea
Love these interal doors - Interior Steel Windows Sao Tomas Felipe Hess
11 converted attic bedrooms to inspire you. Amazing transformations that prove we all need a bedroom in the attic. For more converted bedroom and attic bedroom ideas go to Domino.