A plugin to modify the TinyMCE editor in WordPress 3.9+. Now available on WP.org! https://wordpress.org/plugins/mrw-web-design-simple-tinymce/

readme.md

Now available in the WordPress.org Plugin Repository: https://wordpress.org/plugins/mrw-web-design-simple-tinymce/

mrw-tinymce-filter-example.php

<?php
/**
 * Example filter to add text style to TinyMCE filter with Mark's "MRW TinyMCE Mods" plugin
 * 
 * Adds a "Text Styles" submenu to the "Formats" dropdown
 * 
 * This would go in a functions.php file or mu-plugin so you don't have to modify the original plugin.
 * 
 * $styles 	array 	Contains arrays of style_format arguments to define styles.
 * 					Note: Should be an "array of arrays"
 * 
 * see tinymce.com/wiki.php/Configuration:style_formats
 * see also tinymce.com/wiki.php/Configuration:formats
 * see also also wordpress.stackexchange.com/a/128950/9844
 */
add_filter( 'mrw_mce_text_style', 'mrw_add_text_styles_example' );
function mrw_add_text_styles_example( $styles ) {
	$new_styles = array(
		/* Inline style that only applies to links */
		array(
			'title' => "Link Button", /* Label in "Formats" menu */
			'selector' => 'a', /* this style can ONLY be applied to existing <a> elements in the selection! */
			'classes' => 'button' /* class to add, could be multiple, space-separated */
		),
		/* Inline style applied with a <span> */
		array(
			'title' => "Callout Text",
			'inline' => 'span',
			'classes' => 'callout'
		),
		/* Block style applied to paragraph. Each paragraph in selection gets the classes. */
		array(
			'title' => "Warning Message",
			'block' => 'p',
			'classes' => 'message warning'
		),
		/* Block style capable of containing other block-level elemeents */
		array(
			'title' => "Feature Box",
			'block' => 'section', 
			'classes' => 'feature-box',
			'wrapper' => true
		)
	);
	return array_merge( $styles, $new_styles );
}

mrw-tinymce-mods.php

Now available in the WordPress.org Plugin Repository: https://wordpress.org/plugins/mrw-web-design-simple-tinymce/

This example causes duplicate styles dropdowns if other plugins add stuff ( like enlighter plugin )
You guys should try using https://wordpress.org/plugins/advanced-tinymce-configuration/

I've been using this for months now and it's worked perfectly...but now I need the Anchor button so I added 'anchor' to the $buttons array...but it does not display? Is there something special about the Anchor button that needs to be different? Also, is this the full list of buttons that can be added?: http://www.tinymce.com/wiki.php/Controls

@cbournak Check out @ryanderson's (I think that's whose it is) question on WPSE. I believe the table buttons suffer from the same issue in that WordPress doesn't include that TinyMCE plugin by default. You'll probably need a plugin like MCE Table Buttons to get it working. (And for the record, I much prefer using TablePress as it discourages users from getting all layout-happy with their tables.)

@bryanwillis You're right that that's a limitation of this plugin which I mostly made for personal use. I prefer the styleselect for it's custom text styles functions that aren't available in the Formatselect.

For anyone who missed it above, this is now a plugin: https://wordpress.org/plugins/mrw-web-design-simple-tinymce/