Thanks for responding. What you describe is more or less what I am doing now (although making a book with various templates to copy/paste from is a nice idea I hadn't thought of) and in this case it is a good solution requiring not much more effort than being able to pull in a template through the editor.
The reason I asked the original question more generally is because there seems to be other options and features in the generic TinyMCE app that were not implemented in Moodle that I would like to have.
Specifically I want to be able to embed swf files with a transparent background (without editing the html of each book chapter). If you have any ideas for this one - please let me know!