I am trying to retrieve the LayoutID to use in my listing request via GetDescriptionTemplate call. However the response does not return any LayoutIDs. Am I missing something?
The LayoutID identifies the Layout template to use when displaying the item's description. The value in the <Type> tag of the GetDescriptionTemplates response indicates whether the <ID> is either layout or theme. Your observation is right - no LayoutIDs are returned.
Please note that the PictureLayout feature has been deprecated. Therefore GetDescriptionTemplates resopnse does not return the LayoutIDs.