Quote Originally Posted by Biffoniacus_Furiou View Post
If you want to be using spells to deliver sneak attacks, then Sorcerer is the class to use. According to the Rules Compendium's section on precision damage, which includes sneak attack, any special attack (such as a spell) that makes multiple attacks only adds precision damage (sneak attack) to the first attack it makes unless that special attack takes a full round action or longer to activate. For example, a Scorching Ray spell that fires three separate rays normally only gets sneak attack on the first shot, since it takes a standard action to cast, but a Sorcerer spontaneously casting it with a metamagic feat takes a full-round action to cast it and gets to add sneak attack damage on every attack it makes!

Make your character a Spellthief 1/ Sorcerer 4/ Unseen Seer 2/ Spellwarp Sniper 5/ Arcane Trickster 8. Get the feat Master Spellthief, use metamagic like Split Ray and Invisible Spell, and consider picking up Heighten Spell with the Acidic Splatter reserve feat so you can always count your highest-level available spell slot when activating it. Keep in mind that bonus damage such as sneak attack is always the same type of damage as the attack itself, so a Scorching Ray will deal extra fire damage and an Acidic Splatter will deal extra acid damage.

Ugh stupid Spell compendium. Yeah ok then sorcerer is the way to go. Just invisible or twinned telekinesis.