Something like this?
This message should have a "Bookmark" link next "Table of Contents". Clicking it pops up a dialog box asking your permission to add the URL to your favorites.
Works with IE, not with Mozilla (yet). However Mozilla does it is different than IE.
The link will start showing up in new messages. I could force all messages to have it retroactively by deleting the generated message HTML files, but that's kind of a radical step. Let's try this out for a bit.