I've just read this all the way through and it rang horrible bells. My DS2 was exactly like your ds. The refusing to go to sleep until after midnight (then he would be up in the middle of the night wandering around) particularly. Mine once punched DS3 in the mouth during a car journey (he was 7). There was blood everywhere it was horrible. He was contrite afterwards & "didn't know" why he'd done it.
The first doctor we saw said his problems were down to bad parenting, and a father who worked nights ("if you could just get a proper job dear?").
I went to parents support meetings & forced myself on a new doctor in the next town who was giving a presentation, and begged him to see my ds. After the first consultation he dx ADHD & we've never looked back.
I'd hoped that things were better now, but it sounds like nothing has changed. Can't suggest anything to help I'm afraid, except that the thing about "if he can concentrate on the PS2 then it isn't ADHD" from further down the thread is a load of cr*p. These children can hyperconcentrate on something they are interested in. My ds is TV/Computer orientated and could be on them 24 hours a day, but can't remember "put some socks on" for the time it takes to go to the drawer.
Which area are you in?