Hidden doors -- This company makes cabinets, bookshelves and anything you can think of that fits your existing doorjambs thus hiding the door (and also making use of the space) Not sure I like the idea of a 'gun cabinet' door.
how to make a secret door a room or closet. I think we'll figure out how to do this for double doors. I have double doors between my sew/craft room and what will be the dining room. more storage in what would have been lost space .
In Manhattan’s landmarked Tribeca North area, the top floor and roof of an 1884 caviar warehouse are reconceived by New York-based Andrew Franz Architect as a loft with a large open entertaining zones and a fluid connection with the outdoor environment.