The Crimson Binome
Hero
Unfortunately, since they're regular attacks and not touch attacks, you'll be lucky to hit with more than half of them.Wand of Holy Ice cl 15 + rogue 7 (4d6 sneak attack) = 292 average damage if all attacks hit. It requires a flat-footed target, but it is a very nice opener for a rogue.
Of course, you could also just go pure Rogue and max out your Use Magic Device, bringing your average damage-on-all-hits up to 540 (or an even 600 if the bard is singing).