Oh, tantrums at four, yes, we're coming up to that again. And I know just how it seems worse - unlike your average 2 year old, a 4 year old can reason (somewhat), can talk, can walk, can feed themselves, can go without a nap, can take themselves off to the loo. So there seem fewer and fewer excuses for a trantrum. You don't feel able to put it down to simple tiredness and frustration, even if these are factors. And for me, don't know about you scummy, it was the sheer size of my ds at 4 years. When he kicked, it hurt, when he screamed it was really,REALLY loud, when I had to carry him upstars he was B*** heavy.
WWW has given a great rundown of tactics and you've said you use all the usual ones, too. Can't add more. My favourite is sending ds up to his room - a very final and in a way a non-violent but physical answer to a partly physical display of temper. I always said (lets be honest, still do it sometimes, so still say), go to your room I will not have that attitude. Very very important, imo to get across the fact that the attitude is unacceptablem, not just the crying, hitting etc. As they get older, you know they can reason and have some self awareness, even if they deny it. Make sure they know that you know it.
but scummy I know that point you come to - you realise that no tactic is going to work 100%.- look at my son with his cub leader!
Another possibility is to try and rework some routines, re think ways of doing things with your sons. Perhaps different rules about sweets, dressing etc. Still your same principles, just a different way of carrying them out. Possibly even involve your ds in discussing the change of practice. That can be a good anti tantrum device. Take away the accepted barriers if poss, it might take your ds a whild to get fed up with the new ones, when he does, change them again. I tend to re-work the fine details our morning rountine every few months. Still don't have peaceful mornings, though. No magic solution.
I do remember thinking how much nicer my son was as he grew older - the massive tantrum stage does pass, the testosterone subsides, it is a phase. You're nearly there, honestly. In a year or so, if you're like us, you will look back and think, phew, glad most of that's over and done with.