"Patch 5.4 Feature Preview"
Q. When will Connected Realms be available?
A. We haven’t yet determined when we’ll be creating the first Connected Realms, but we expect it will be some time after the launch of Patch 5.4.
They really shouldn't call this a "Patch 5.4 Feature" if it's not going live with Patch 5.4. They really should word their title better, unless this is something they can modify without patches, and they'll slowly be creating new "server clusters" throughout 5.4. Lot of people believe this is happening when 5.4 releases, and that doesn't seem to be the case.