1 – I would think that the qtranslate plugin will add the tabs to the wp_editor() editor automatically.
At least , it was doing it when I used it for CPT ..
2 – there is this plugin which helps plugin authors to implement qtranslate in own plugins .
3 – there is a filter add_filter(‘the_editor’, ‘qtrans_modifyRichEditor’); in qtranslate you might want to investigate
4 – you can also use a simple loop in order to create the tabs using qtrans_getLanguage()