I own and play OA, and can say that Plane Sailing is correct. Iaijutsu Focus is very nasty and can occur outside of an iaijutsu duel.
Some common feat combinations to maximize effectiveness:
Way of the Scorpion (Rokugan) Get Int and Dex mod to dex
A Single Moment (Rokugan) Refocus as MEA
Improved Feint (Evil Handbook) Feint as MEA w/ +4 bonus
Ultimate Feint (Evil Handbook) Feint as free action
Expert Tactician (S&F)
Expert Timing (Kingdoms of Kalamar) Basically, lets you count as having a readied action each round. You can act without changing your initiative.
Quickstrike (Traps & Treachery) If target is damaged by a sneak attack, you get additional attack at same bonus 1/round
And the worst feat: Versatile (Rokugan) Choose two cross-class skills; these class skills are always considered class skills no matter what class you take.
I would put pre-requisites in here but that would be a copyright violation. Have fun building your super rogue/...
If you have any further questions, I'll keep up with this thread.