This site can convert text from any case to any case.
Specific Tiny MCE Standard Styles
function custom_wp_texteditor_styles ($arr){
$arr['block_formats'] = 'Paragraph=p;Heading 1=h1;Heading 2=h2;Heading 3=h3;Heading 4=h4;';
return $arr;
}
add_filter('tiny_mce_before_init', 'custom_wp_texteditor_styles');