It is very real -- I am living proof. :) I choose my own hours for work, and often sleep twice, and my rhythm varies between being awake during the night and the day. I do think that not everybody is like this though.
Will a sufficient amount anecdotal evidence turn into proof?
In any case, I was getting worried that too much coding had destroyed my health, it turns out I am may have gone back to sanity instead; the article certainly made my day.