[Al Skierkiewicz]

Jane,
Our fake tree has a large dowel running up the middle to which all the branches attach. It would fit into the tree stand either way. However, gravity keeps all the branches in place. I am not sure they would stay put in an inverted position.
A quick search showed that manufacturers have been making inverted trees for a few years. Although the practice started in the middle ages in Europe, it appears to be more of a floor space saving effort than anything else. Those consumers who have used them in recent times, like the fact that ornaments are more visible.
A simple attachment can be made once the position of a beam is determined. A screw eye or other threaded device for wood would make a small hole in the ceiling and could be used throughout the year for a hanging basket or planter.