Greg, The T710 does support Server 2012 (Standard & Datacenter). As far as the SMTD disk, it was stopped around the release of Server 2008 as the drivers for our controllers are already present on the OS media. Allowing you to just boot to the OS media. The same applies to 2012. So you should be able to boot directly to the media to install.  On another note, support.dell.com does have a OS dropdown which has Server 2012, so we have drivers released for that OS as well. Let me know how it goes.
Will Windows 2012  install on a PowerEdge T710?  Is there a Systems Management Tools and Documentation version that will have drivers for a  PERC 6/i and Windows 2012?
Windows 2012 on PowerEdge T710