Regarding a "Dawn of the Dead" extreme extended Cut:
there is a german languaged DVD containing a PAL 155 minute cut. This is, afaik a "we put every piece of the Romero and the Argento Cuts togerther in one cut" released on DVD. There are differences in PQ, AQ and Score while the movie. I remember that there also "score jumps" in some scenes. It is called "Ultimate Final Cut"...