A long time ago Molten used to work on Clustered Load Balancing which would allow world servers for each zone and things such as cross-realm BGs and Arena.
As far as I am aware the CLB development was stopped before the moltdown and never continued.
Now recently I have seen that there are already some private server out there that have working Cross-realm BGs and Arena so it doesn't seem to be a impossible task to develop that.
Im wondering what Warmane is going to do when the development of Lordaeron is mostly done. Maybe Cross realm would be something to aim for?
Cross realm would be beneficial in many aspects:
- Higher population capacity for Icecrown.
- Cross realm Arena between Icecrown, Lordaeron and Blackrock
- better latency in Arena
- etc..

