Q 155: Is there a feat that allows you to turn a weapon that is not normally a monk weapon into a monk weapon?
A 155: Three in the Eberron Campaign Setting: one for Longswords, Longspears and Twobladed Swords. Secrets of Sarlona also has Polemaster, which lets you add Poleweapons to your Monk weapons.
A157: It's not so bad as a Wizard/Arcantatrix//Druid/Planar Shephard, but it's still very, very good. IMO, over the required power level. (Btw, drop the Eldritch Knight for Swiftblade levels, and don't worry about Twilight on your armour as an Abjurant Champion. I would also replace Fighter with something useful, like Warblade.)