I´ve managed to edit it, so I can see now my favorites under my_youtube_user_ name .

It does not require any password entry, because user favorites are anyway public.
But how to add "search" option is unknown for me. Anyway, youtube API is something new for me and to understand PHP also

, so it is not an easy way to edit or create search function into available youtube plugin.
But here are windows app for that, that you can over that search and start youtube videos.
Look here:
Dune Control for Windows
Edit:
There you can download youtube.php file, where added four channels under youtube videos icon.
Two first of them added by me and two are user Juniperus channels. Added channels are first four.
First channel is youtube user favorites channel (if you are youtube registered user) and before replasing this modded file with original you must first replase word "username" with your youtube account username.
Save modifications and replace original toutube.php file with this modified youtube.php in youtube .zip folder.
Then you just uninstall old youtube plugin and install this new one.
And of course you can add your own favorite channels. This file is only as an example.
PS. I´m using notepad2 as php editor.
http://www.flos-freeware.ch/notepad2.html
Download here youtube.php file..