If you wanted to make this simpler, and don;t mind going into debug mode on your site, you could edit the Option Code for Mobile Style boxes in AdminCP so that all styles (both mobile and standard) show up and then you could replace the styleid numbers in the plugin above with $vbulletin->options['mobilestyleid_basic'], $vbulletin->options['mobilestyleid_advanced'] and $vbulletin->options['styleid'] then if you changed styles down the track you wouldn;t need to edit the plugin by hand. You would still need the above plugin to make it work.
To do this change the Option Code to:
PHP Code:
select:eval
//options = fetch_style_title_options_array('', false, 'mobile');
$options = fetch_style_title_options_array();
$options = array('0' => $vbphrase['none']) + $options;