VERIFIED SOLUTION i

Prevent re-install of the Portrait Foundation SDK Visual Studio templates

When installing the Portrait Foundation SDK, the installer always attempts to re-install the Visual Studio templates. If they are already present, the user is forced to choose whether to overwrite or ignore each existing template.
This is time-consuming and would appear to be unnecessary as these templates do not change very often.
Unfortunately, this all happens within Visual Studio plug-in code rather than from the Portrait Foundation SDK installer code. The easiest way to prevent this from happening is to close the Visual Studio Content Installer wizard rather than hitting Next (or Finish).
Alternatively, you could try opening %userprofile%\Documents\Visual Studio 2010\Templates, and deleting all of the Foundation-related *.zip files. that should remove the existing set of templates so that you don't have to go through the 'Rename, Overwrite, or Skip' option for every template.
UPDATED:  March 31, 2017