I am the representative of the Russian Riftgame project.
As you, possibly, know, currently Rift game do not provide possibility to chat by the Russian characters - the problem for a lot of Russian gamers.
Let me wrote about project we planed:
Provide a possibility for rift users to use UTF-8 encoded characters on chat.
It may be some client patch, but I think it is really hard (if possible at all).
Best solution - is an addon that would provide ingame chat. Alike system used by xfire.com addon, that provides those who stream to chat with users online, just ingame.
It may be simple form with integrated chat.
Important thing is that addon should offer possibilities to create channels and inviting users online on it.
This addon may be interesting even not only for Russian games, but also for those players that want's to chat by the group. Budget: 500 USD.
The API doesn't even begin to offer this sort of functionality. You should post the request on the official rift forum so that Zorba (Rift guy in charge of API/addons) can tell you if they can add this to the API or the base client code.
A simple request to have the default client allow typing of UTF-8 characters is surely far better than hacking about with addons?