I believe it is possible to do gather this data from iTunes, at least on the Mac, and if it is configured to sync subscriptions with your iOS device. There are people writing AppleScript against iTunes + Podcasts, managing listening, subscription, etc. So, that is a sign that it may be possible.
I personally have it on my list of data to collect. At the moment I am working on extracting the SMS, iMessage, and related data from an iTunes iOS backup directory and insert it into my personal database.