EWP- Spiked Chain. This gives you reach. It is also a Shadowhand Weapon, meaning it works with your Shadowblade Feat.
Combat Reflexes- Lets you get optimum use of said chain to do lots of AOOs.
Power Attack- Mostly taking it so you can get....
Cleave- Even MORE attacks this round! Even on an AOO! Don't get great-cleave though. That one's for suckers-- it rarely comes up enough to waist a precious feat slot on. However, adding Mighty Cleaving to your Spiked Chain would be worth it.
Improved Trip- Free attack if you trip an opponent, and chain can be used to trip, AND a lot of Setting Sun maneuvers utilize trips (and give bonuses)
Items to use-
Potions of Enlarge Person (or have someone cast it). Extends reach of the chain to 20', giving you LOTS of potential AOOs.
My Monk 15/Swordsage1 had this feat combo, and got 5 attacks/round on his turn, and 4/round when it was not his turn from getting so many AOOs and the occasional cleave.