ID3v2 tag editing - how I wish I could use Xml

Trying to edit various tags in my music collection.  The good news is that there is a standard data format, namely ID3v2.  The bad news is that the files can't be edited easily.  Specialized tag editors are needed to embed the artist name, album, genre etc into the mp3.  There is an awesome one I've used called Mp3tag.  Its free and works very well.  But things like embedding the album cover art is impossible to do.  Let alone other automated tasks.
I find myself wanting to get into the details of the tagging and perhaps write some scripts to automate some tagging tasks.  And I keep thinking I'd like to be able to use Xml to manage the metadata.  I could get the tools and edits I want done very fast.  And no need to get some specialized editor that has only some of the features I want.  Xml is just text, so any text editor would work.  And it manages delimited metadata very well.
Until the standard changes, I'm stuck using someone else's tool.