It is my belief that the shelf between the two hammock beds in the Vertex does more than just make for a handy place to put stuff. I think it plays into the independent suspension (if you will) of the system. There is a separator piece of fabric that runs the total length of the rig, so the two hammock beds don't actually attach to each other directly. Pretty sure it runs completely top to bottom, but if not, it is sure close. Bear in mind, it was almost 3 years ago that I got to play with a Vertex, so memory and design changes might be an issue.
I plan on getting a Vertex in the very near future. A pregnant Genuine Draft has kind of made that decision for me. Our plan is to use the fabric between (shelf) as a baby crib for the woods. Regardless, I should be able to provide some better Vertex insights in the next few months.