I had an idea of how to quickly deal a very large amount of single target damage.
If you are a /Ninjitsu Stalker, or if you take the power Misdirection from the Concealment pool, you will have 2 placate powers.
Then include Burnout from the Speed pool, and maybe Adrenal Booster from the Experimentation pool for another Build Up type power.
The power chain idea is -
Build Up, Assassinate, Placate, Burnout, Build Up, Assassinate, Placate, Adrenal Booster, your t9 extreme damage attack (Golden Dragonfly for Ninja Blade, for example), Smoke Flash/Misdirection, your next strongest attack (Soaring Dragon for Ninja Blade, for example).
It could be fun to try. I'm working on a Staff/Ninjitsu now.