Since you can only deploy one master TFS server and replication mechanisms are not supported you might consider using a TFS Proxy server, which caches the downloads from the Team Foudation Version Control.
Functionality / What it does:
Cache downloads from Version Control only. Control Messages and other artifacts like work items are still transferred directly between client (Visual Studio) and server (TFS).
Read more about how the proxy works.
From a licensing perspective the TFS Proxy costs you one (additional) TFS license.
See also: Licensing whitepaper.
You find the installation files on your TFS CD under Proxy\setup.exe.
After the installation is complete you need to modify the configuration file.
See also: hardware requirements.
More Information (including all links mentioned above):