This seems to be a recurring subject in this group.
Mathematica is now at version 8 and there's still no multiple undo and redo functionality. I don't understand how such an amazing piece of software can lack such a trivial feature. Why isn't Woflram doing anything about it? Heck, I'll even write the code for undo/redo myself for them for free if they let me. Is there someone at Wolfram I can complain on the matter? Perhaps an internet petition is in order? What do you think?