I have my doubts as to whether the 1994 cent you referenced is actually a doubled die. I believe these maybe the result of die wear, hub wear, or something other than hub doubling. I would have to see a number of additional coins to make a determination like that stick in my mind, but I will be hesitant to list any more dies like this one and the referenced 1994 until I have a good chance to study the subject in more depth.