Just to keep this bunk information all consolidated on the most recent thread about bunks, Sequoiacoast devised a really clever solution for a temporary mid-bed bunk without using the slings that resemble the OEM bunks (although those are very cool as well).
You can check it out on her Full Monte type resto thread, toward the middle of this page:
http://www.airforums.com/forums/f116...-26932-13.html
I love her idea and execution, and will most likely incorporate something like it when I get an AS of my own.