Staircases take up a lot of space, so why not use them for storage as well. Imagine each step is a box with a hidden drawer in it still allowing for additional storage or home office space beneath the staircase.
Attic Bedroom Closet Design, Pictures, Remodel, Decor and Ideas - page 9 - sublime-decor. I have the perfect wall (with attic behind it) to do this. I've often thought of making an easily accessible closet there.