They've been facinating me for ages so I finally gave in and did one..
I'd really be interested in seeing your one if you do. You're already really good.. so even a small improvement would be a super big deal. The improvement curve kinda flats out as your skill set increases, I believe.
Hmmm well, I just took a look in my gallery and I posted my first ever digital painting (Sherlock in profile) on the 21st of Jan 2012 so maybe I should repaint that for the 21st Jan 2014, that could work! I did touch it up a little while ago though so i'd have to see if I still have the original or it wouldn't be a very fair comparison.