Michael Trebilcock released a new version of his super YT 2.8.
Here is my MorphOS modification http://ghh.8u.cz/friends/YT_2.8mod.lha
There is a "ytplay" program in the archive that will run another modified ytplay.rexx script with the video address in the clipboard.
In the yt.conf file, edit only the path to mplayer.