Linking users and content through taxonomy.

I'm using the 'Term_access' module to create permissions between a user and content based on a shared taxonomy term.

For instance, if I have a 'media' taxonomy with 'TV', 'Movies', 'Music', and 'Books' in it, and I assign 'Books' to a user, that user will only have permissions to edit content with 'Books' selected using the same taxonomy vocab. That's set up, working, etc. The *problem* is that when a user is *creating* or *editing* content, they have the ability to change the taxonomy term to something they don't have permission to edit. What I'd like to do is either find a more 'robust' module that takes this into account, or alternatively alter the content create/edit form to remove the terms that the user doesn't have permission to create/edit.

Any thoughts on how best to achieve this? Thanks!