Returns the roaming AppData directory for the installed ArcGIS Desktop.

def appdata_roaming_dir():
    """Returns the roaming AppData directory for the installed ArcGIS Desktop."""
    install = arcpy.GetInstallInfo('desktop')
    app_data = arcpy.GetSystemEnvironment("APPDATA")
    product_dir = ''.join((install['ProductName'], major_version()))
    return os.path.join(app_data, 'ESRI', product_dir)