I can see here that with Oracle we can use load balancing across two CM database instances in an active-passive fashion. My question is, is it supported to scale out the Content Manager database (with SQL Server) to be active-active with 2 instances of Content Manager? For example: in North America there is an instance of the CM and in Asia there is a CM and they share a distributed database.
An active-active setup is not officially supported for Tridion CM MSSQL db. However, you should be able to use SQL Server's AlwaysOn feature