Thanks for the question, Ferdy.
I have to say that I get this question more than I do any other one. It seems that many people either weren't satisfied with the ending of Eagle-Sage or just couldn't get enough of those characters and that world. Clearly, I'd like to believe that the latter is true, but I have a feeling that the question has more to do with the former....
The short answer is that I have no immediate plans to go back to LonTobyn. I'm working on Blood of the Southlands now, have a contemporary fantasy series that I've started and am trying to find a home for (writer-speak for "I haven't sold the series to a publisher yet"), and already have in mind what I want to do with my next project.
The longer answer, the one that's harder to explain to readers, is that I don't have the passion for LonTobyn anymore. It was my first series -- Children of Amarid was the first novel I ever wrote. It didn't appear in print until 1997, and the whole series was only three books, but I lived and breathed LonTobyn for eight years. Because it was my first series and I was trying to get myself established as an author, because my parents both died while I was writing the series, because my daughters were both born while I was writing it, my feelings about the books, the characters, the world, etc. were incredibly intense. When I finished Eagle-Sage, I was relieved to be done with it and eager to do something -- anything -- else. So on the one hand, I was burnt out on the world when I finished and I've never quite gotten over that.
On the other hand, while I'm still proud of those books, I've always thought that I could do better both in terms of the writing and the world-building. That belief has been borne out by my experience with Winds of the Forelands and now Blood of the Southlands, which I believe are superior in every way to the LonTobyn books. So not only do I lack the passion for LonTobyn, I also am not drawn back to the world.
The reason I turned to Blood of the Southlands after the Winds books was that I felt that the world I built was and is rich enough to sustain many more tales. I don't know if I'll go back to the Forelands/Southlands once I'm done with this new project, but I know that I could, that there's enough in the world to fill many more books. I don't believe there's that much left to be mined from LonTobyn.
Finally, I ended Eagle-Sage the way I did intentionally. I wanted to leave future possibilities open for all my characters, and I wanted my readers to imagine for themselves what might happen to Cailyn, to Jaryd, Alayna, and Myn, to Orris and Melyor. I have ideas about what became of them all, but I'm not sure I want to publish them, because in a way the ideas of all my readers on the subject are just as valid as my own.
Anyway, those are my reasons. I hope you understand, and I hope you'll give my new projects a look, even if they're not what you were hoping I'd write.