Very nice...I think I may actually use this. I was going to make my own, but never considered making it ToB. Works well. I also was planning on including something similar to your Iaijutsu damage bonus on round weapon is drawn.

One idea, as an improvement to Iaijutsu Master and a sort of capstone, is that during the round it is drawn it is Vorpal.

Another thing I can envision is some bonus to criticals. It seems applicable for a Samurai.

Seems like all of it is straight skill, so I can't think of any of the abilities being lost if you become Ronin. That'd be awesome though. I set up a system for repentance from Ronin: find a Daimyo who will accept your services, work for him for a year or two, then commit Seppuku and get resurrected, probably at your own cost.