It's a bit too early to tell. As of the most recent rumors I've heard, the Tau are still pretty distant. The next thing coming down the pike is probably 6th Ed, and the regular Marines, Chaos Marines, Dark Angels, and maybe even Sisters are likely to get treatment before the Tau do. I've heard reports that the studio isn't even giving them a lot of serious thought right now.
Bentu, do you have links to these rumors you're discussing? I might suggest posting them up on the Rumor Mill if you think they're reliable. I'd be interested to hear them, at any rate.