One other option that has worked very well for me:
Make the 2 bottom support pieces extend out about 3 or 4 inches, but then add another 90-degree elbow out there at the end and connect them to each other . . . so the two supports are connected to each other by "outriggers", and the whole thing makes a large rectangle on the floor.
The width ends up being 8 - 10 inches (because the 90-degree bends add another inch or two), and the length is however long you make it (mine is about 14 inches or so).
The advantage of this is that you do not have to glue it . . . assembled, it is VERY stable, but still breaks down completely for easy carrying.
I'll try to get a digital picture together and post it.