There is a quest in the Mage Guild that requires you to enter a Mage's dream name "Through A Nightmare, Darkly" for Henantier. As soon as you enter, the text states that you lost all your items but will keep your skill levels. However, if you have a quest item such as the Ring Of The Vipereye or Boots Of Springheel Jack, you will keep the bonuses, even after you get out of the dream and get your items back. The items will not be equipped but the skill bonus will still be there. You cannot re-equip the items, but you can equip other rings or boots and get their bonuses as well.