It's been a while since I checked this thread, so excuse me for having not gone back to read every page...
I have this same issue with my tab (as noted way back on the first few pages)...tried the screw tightening which seemed to only temporarily improve it. I knew it wasn't a big deal as the tab worked just fine, but it still bugged the crap out of me.
While I haven't a true solution to the issue yet, I will say this: I bought one of the
official cases for mine from the Google Play store, and with the way it fits over the tab, it completely eliminated the problem for me! For one, I can't see the raised edge anymore because the case covers it, and 2nd, it places a tight grip around the tablet and there is no more creaking or play when holding it either. I was always planning on using the case anyway, so for me, problem solved.
Again, I apologize if this was already mentioned, and I also realize for some this "fix" may not be acceptable based on your intended usage...but wanted to toss this out there none the less.