we have several successful scenario/projects with adf  11g in more than 3 big enterprise in Iran there is no problem with farsi but you need to buy some persian  component and standard from companies that has developed them.such as the farsi version of the af:inputdate... or the farsi version of all english word used in component such as "view" in af:table...
at the moment one of your system has more than 800 users and it is performing really good  it is totally developed with adf 11g and we spend about 5-6 mellion tomans regarding the buying of the library/persian/standards.