Clearly Canon had this "adjustment" built into the firmware. Apparently NO ONE at Canon USA knew about it though SOoo, we iPF5000 owners go through all kinds of hoops trying to figure out what is going on. If there had been decent documentation, it probably would have never been an issue. Anyway, I did the adjustments and my printer is purring just fine.. Love it.
Now that your banding problem is fixed I am going to declare this an "official" end to the problem, as you were one of the first ones to bring this up (and loudly). The strange thing is, this adjustment (Far End Band Adjust) is not new to the firmware. It was certainly there in version 1.08, although there were 20 patterns instead of 32. Probably you could have fixed the problem months ago if someone just told you what to adjust!
Now if we could just get the Photoshop plugin to center EVERY print and use Black Point Compensation when Relative Rendering Intent is selected, we would be in hog heaven...