I found this article at the Arizona weaving archives.
www.cs.arizona.edu/patterns/weaving/articles/hc_32_01-2.pdf
It details how to do a couple of 4 shaft weaves on 2 shafts without pick-up sticks or anything to create an extra shed. Its basic, but adds more to the rigid heddle repertoire, without any special techniques having to be learned. The patterns are on the last page.
Enjoy!