Sorry, no photos of the "lip." It was something you could feel in your stocking feet under the carpet, between the foot of the bed and the dresser, running fore and aft. Creaked pretty good if you stepped on it. The service write up for it was pretty extensive. They pulled the bed and slide mechanism out, the carpeting, along with the mirror doors and washer/dryer in the closet and replaced the decking and welded some 1x1 support angles in someplace. Opened up the front cap, too. All under warranty in Oct., 2009. The motor on the awning was also replaced during that "visit." That's another story.
So, my advice is if your trailer is still under warranty, or even if it's not, if the floor squeaks, get it checked out. Could be minor, could be major. The main reason we took our rig in was the awning motor. I mentioned the bedroom floor squeak to the Service Advisor as we were going through some other adjustments I wanted on the rear slides, almost as an afterthought. She dug into it and called us with what she found.