there is no more information. As RIM employees that's pretty much all the info that is given out. There are lot's database servers and a few third party applications that sit on top to allow RIM to manage all the device provisioning and server connections.
I doubt there is anyone that works on the infratructure itself that would risk their job because a few of us are curious about how it works
I also heard that one will be built in Slough, UK. I also heard one was being built in France
It makes sense one would be built somewhere in the Continental USA as presidential email gets routed through the relay. The main reason behind opening a tech support centre in Texas was not just to get more spannish speakers but because the Americans would prefer Americans with security clearance providing support for military installations