Since this has obviously been patched by Bethesda, this is in response to a ton of people asking me on Xbox live if I can tell them how to do it.

The ONLY working method of duplicating armor or the Oghma Infinium is to clear you xbox cache and play a new offline game.

To clear your XBox cache go to System -> Settings, highlight the HDD and press the Y button. Select Clear Cache and load up Skyrim. When prompted, deny the update, play in offline mode, and start a new game. What this does is removes any patches for your XBox games so you can play them in their original factory form, but only if you play them offline. (ie; no achievements..)

Now with that in mind just use the cheats as they were originally before anything had been patched and you'll be level 81 with all skills at 100.

Note: This is a great game despite the crazy bugs and glitches, try to play it through before you spoil it by cheating.

Wonder how long it will be until someone finds a new work around. I remember in Oblivion as soon as they patched out the arrow duping people found a way to do it by dropping scrolls.