So... I've edited HtmlEditorField.php, tinymce.template.js, and all the css files I can find, both in template and other directories...
And I still cannot seem to customize the Styles and Format dropdowns in TinyMCE. I do not remember having this much of a problem in 2.3rc. Editing tinymce.template.js did allow me to remove certain buttons, but the dropdown contents are not listed there. I have searched high and low through .css files for "MsoNormal" etc., with no luck. Where are these styles contained?