Nope. Nothing more has been published about them yet. Well, I take that back. A tiny bit was written in the Era Report: 3145 and Field Manual: 3145 books, but they don't really expand on what's in the novel much at all.
Not only that, but TPTB at Catalyst Game Labs have said that the epilogue to Surrender Your Dreams is no longer necessarily considered canon.
Surrender your Dreams:
[18:02] I appreciate that the post-Dark Age setup is not open for discussion, but there was one thing I wanted to clarify; are the events of the epilogue in Surrender Your Dreams still considered canon, or is that glimpse of things post-3145 no longer valid?
[18:04] <@Habeas2> Nerroth - We are not necessarily considering the epilogue for Surrender Your Dreams valid. It would be too restrictive to upcoming plans.