I am recruiting for banter writers atm for any and all Bioware NPCs (except Sarevok) with Yikari. If you're interested, or want to follow this exciting NPC, please FOLLOW THE LINK IN MY SIG!
v1.0 has already been released, and will shortly be availiable from FW. However, although bug-free, he is far from finished. Here's some info:
"This is a NPC for BG2. He is a monk from Kara-Tur. His name is Yikari and can be found in the Temple District in Athkatla (on the bridge generally in the middle of the area).
He has his own quest (sort of). It is to get Celestial Fury from the Guarded Compound in the Temple District. He has taken a vow of silence until he gets the sword. However, he is rather less objectionable than Kuroisan

Depending on whether you have CF (+3 or +5) when you meet him, he will still be bound by his vow of silence. This affects his equipment, biography and dialogue.
You can persuade Yikari to join your party even once you have got Celestial Fury, however a charisma check is made to determine whether he will insist he keep Celestial Fury or whether you can give it to whomsoever you please. Despite being a monk, Yikari is "skilled" in use of the katana, not "proficient".
If you try to kick Yikari out of your party once you have Celestial Fury he will ask for it before he leaves. Again, if you want to keep it without forcing violence, a charisma check is made. The ring of Human Influence on Player1 is your friend.

If you let (or are forced to) let Yikari keep a personal watch over CF then only he can use it, it is worth nothing and if you try to kick him from your party without him holding it he will turn hostile. You can only get the original CF from the Yikari-only version from telling him to his face and fighting him. I'll have no betrayal!"
For information on writing for Yikari, please go URL=http://www.shsforums.net/index.php?showtopic=9791]here[/URL].
There are also sample banters for Edwin, Imoen, Minsc and Yoshimo, although I have written others.