I've developed an addon plugin that allows you to set the id3 tags in the mp3 file directly from the sermon data. i.e. it sets title, preacher etc. and inserts the album art when the sermon is saved.
This allows the downloaded mp3 to have the correct tags, and ensures that the image in the podcast is correct etc. without having to bother setting the tags before uploading the mp3. It also ensures consistency between the data in the sermon and that in the .mp3
The integration with the existing plugin is not perfect (you have to manually update the getid3 library on installation), but if there is any interest, this could probably be tidied up.
Note that this is in a sense the opposite of the existing addon, which updates the sermon data from the id3 tags in the mp3 file