For those who have seen the new "Star Trek" film....... Lorenzo James Henrie plays the young Vulcan bully who goads Spock into giving him a good thrashing by calling Spock's mother a whore.
He's only listed in the credits (to be found at the IMDb.com) as "Vulcan Bully #1". But I put it to you that he is, in fact, Sybok - the elder son of Sarek.
He never really says anything bad about Sarek, only of Amanda Grayson and by extension Spock (who would be his half-brother). So if he was Sybok, he would not have been trashing his father, only the choices he made after his Vulcan princess mother passed away.
Just an idea.....
Live long and BCnU!