The tinkertubes books has a background holder. Here is the download link:
http://www.software-cinema.com/page/tinkertubes
Another simple method is a two by four and a little spring loader device (or the screw type as shown in the examples below) that you stick on one end and then you just push it up against the ceiling and it stays in place (like those old spring loaded lamp poles with 2 or 3 lamps on them). Use two of these and then extend a rod between. I've built several of these over the years as well as a wall spanning book case that goes all the way to the ceiling.
Cheers,
rfs