In a similar vein, how about a spellcasting gadget? A wand of fireballs or similar (probably a bad example as you may be better off with an attack gadget).
Skill Check? Personally I'd require that all variables are selected before casting - but where would you get the spell points from? Extended Battery life? Yourself (which renders it only good for casting spells you don't have - which isn't actually that shabby on 2nd thoughts)?
We'll be handling magic items (and artifacts) in Phat Loot: Fantasy.