When I do top-lighting in-studio, whether it is an octa-box or soft-box placed over top of a person or a soft-box or panel placed over an object, I place the light on a boom arm to get it up and over the subject. A short while ago I was working on a composite in Photoshop at my home office and needed to light and shoot a component in my front room. The object needed top-down lighting which created a problem since the room was too narrow to use my Manfrotto 1.7 metre/6 foot super boom, see image directly below (http://ow.ly/XX8qL).
In my basement I had an inexpensive 2.4 metre/8ft length of 5cm/2inch square wood dowelling, so I clamped it between two light stands, see image below. It was quite sturdy and since it was square rather than round, did not turn in the clamps (Manfrotto Super Clamps http://ow.ly/XX8ec). The only challenge with this very inexpensive setup is changing height, it is easiest to do with two people, one on each stand. Since I was working alone it was easy enough to drop or raise one side at a time by 10cm/4inch or so. This dowelling setup works well with a camera for bird’s eye view—attach a Manfrotto Super Clamp with your tripod head affixed to it, on to the middle of the dowelling. Now you have a reasonably sturdy support for your camera that allows you to get directly over top of an object without any tripod legs showing up. This married with remote live-view on your computer is a great way to work.