SharePoint isn't really designed to support a split geographic installation within a farm.  There is no way to overcome the SQL latency issues that develop and its not a supported scenario.  Yet, there are a couple of options you can pursue:

  1. Build two separate farms, then place services like mysites or shared services like search where they are used most.  These services can then be shared with the remote farm.  It won't solve latency issues for all of your users, but will improve the overall experience.
  2. There are several third party vendors that provide two-way real time replication between geographically separate farms. 
  3. Create two farms, but use DNS so that a user is routed to the farm local to them.  To the user it'd all appear to be the same farm -  but then you'd handle replication between the farms with a 3rd party tool.

Credits

Info taken from: http://social.technet.microsoft.com/Forums/en-US/sharepointgeneral/thread/aaf7af12-4f1a-4c28-9f0c-7f87d46ec2b1

See Also

The SharePoint 2013 Best Practices page at http://social.technet.microsoft.com/wiki/contents/articles/12438.sharepoint-2013-best-practices.aspx