I heard that one of the upcoming Elric books will have magic items (can't remember which one).
Meanwhile I would suggest that if you create powerful magic items yourself, using those should come with a price. These are some of my own thoughts how it should work: using magic item can cause insanity or it drains power from it's user. Personally I believe that wise person wouldn't touch to items of Chaos, Law and Balance and you can invent all kinds of nasty stuff which happens if you use those items too much, even if the item itself isn't evil for it's user it might attract the attention of people who have magical knowledge. Alternatively you can dictate that magic item needs rare and expensive herbs and poisons and long rituals to activate items magical powers. More powerful the item is more carefully you should balance it.