Could you please describe your use case for this, so I can understand exactly what do you mean by "WAN cluster support"?
First off I have to admit I don't fully understand how JBoss supports clustering in a WAN environment. Basically we are writing a management application where there can be management stations scattered throughout the world and they will communicate via some messaging library over the WAN as well as through a local LAN. We need a robust and highly available messaging platform and JBoss Messaging looks like it will meet our needs but I don't understand the implications over a WAN. Any guidance or advice would be very much appreciated.
We have also looked at JGroups but we want to stay with an industry standard if possible for integration purposes.
The release we're working on (1.2) only deals with clustering in a LAN enviroment. We rely on the fact that either we have access to a shared database, or we can use hardware multicast for in-memory replication. Either prerequisite is only satisfied in LAN.
We have plans to extend clustering for WAN in 2.0, but they are not very well defined at this stage.
In our design discussions, we envisioned a scenario similar to what you've described, but we won't provide support for that in 1.2. Regardless of when it will be implemented, it will use JGroups underneath.