Allow wielding some types of traditional magical implements to reduce spell failure rates:

• Wielding a quarterstaff confers the same benefit as wearing a robe but does not stack with it.
• Wielding a wand of nothing confers the same benefit as wearing a robe but does not stack with it.
• Wielding an identified wand which matches a spell (wand of light -> spell of light, wand of death -> finger of death, etc) drastically reduces your failure rate when casting it. Perhaps casting the spell while wielding the matching unidentified wand should identify the wand.