http://blogs.technet.com/brettjo/archive/2009/06/05/white-paper-determining-the-scalability-of-combined-client-access-and-hub-transport-server-roles-in-exchange-2007.aspxThis has been in the works for a while – something new to read on co-located CAS \ HT roles in Exchange 2007 http://technet.microsoft.com/en-us/library/dd901772.aspxen-GBCommunityServer 2.1 SP1 (Build: 61025.2)