As far as I know there are only 3 accounts to have ever broken 5000. I stopped keeping track of those with ratings over 4000, but there are at least a dozen that I am aware of.
@Chessnetwork is the only user to legitimately break 4000, (in the sense that his account was not closed and the rating is acknowledged on his stats page) and it will remain that way for the forseeable future.
Rating of 4000? Is that even a question? Of course people have reached it. Its the first beginner milestone. Me and my buddy hit it within a week. Anything under 4000 is considered pretty amateur. I recommend practicing more if you are under 4000.