Great work! Came across this a while back and had a go at colouring it (hope you don't mind) Just starting to use DeviantArt properly so i uploaded it here [link] (and spent the last 15 minutes trying to track this down so i could give you credit)
Thanks, Benjamin! I've drawn the Joker for DC licensing many, many times, in many, many different styles. The "Clown Prince of Crime" remains fun to draw in most any form though, because he has that winning smile.