While developing my commercial oriental setting - Kaidan: a Japanese Ghost Story setting - for Pathfinder, I contacted Jim Buhlman and he verified that Oriental Adventures is not Open Content, the same is true for Rokugan D20, so copyright prevents that from occurring. That's why I've been developing a distinctly Japanese based setting from the ground up.
I would like to hear the thoughts of the gaming community on converting OA classes to Pathfinder. The Wujen is of particular interest.
Thoughts?
this is definitely something on the middle-future horizon as an official release from paizo. It's not officially on a schedule yet, and no work has been done on it, but we've certainly discussed it plenty and have lots of ideas ready when the "get to work" bell chimes midnight.
Having pulled most of the void rules from most of the Rokugan products, I have to say I encountered no significant difficulty understanding the difference between their IP and OGC. Furthermore, they include a license to use certain IP in certain contexts.Yes the game mechanics of d20 Rokugon are OGC, but you have to be careful because they integrated thier mechanics and their IP so closely by including IP names as part of spells and abilities (they do a poor job of declaring what was IP and what is OGC).

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.