http://blogs.technet.com/mniehaus/archive/2009/06/27/mdt-2010-new-feature-5-support-for-multiple-deployment-shares.aspxWith MDT 2008, you could have one distribution share, which corresponded to a lab deployment point.  You could then have additional network deployment points and media deployment points, with each of these receiving a subset of what was on the mainen-USCommunityServer 2.1 SP1 (Build: 61025.2)