I think I am going to swap Conjuration for destruction in this build. Bound weapons should make for a lighter build, and faster movement. Although, I think archery will also play, as I cannot get away from my love for archery. Maybe name my version Nightingale Shadowsword.....
Try this;
Major Skills - Sneak, Archery, Illusion
Minor Skills - Light Armour, Conjuration, One Handed
Fire off some Illusions from the shadows (with Quiet Casting), then as your opponents are fighting each other, conjure either an Atronach and/or Sword/Bow or any combination, and let loose
EDIT: You could even throw a few Calm spells in there if you don't fancy having everyone tear themselves apart (good for RP)