6 year old won't sleep

[wotsit1999]

I am going to post this on a few boards for maximum coverage! My son turned 6 last week and for about 2 years now he takes hours to get to sleep. He does not get out of bed, he just lies there/rolls around and hats to himself for hours. I put him down at 8, he will drop off around 11. He is exhausted at school. I have tried everything I can think of, but please suggest anything I haven't!! So far tried:
Tiring him out
Changing his diet/less sugar
Baths/lavender
Warm milk
No TV
Bedtime story
Good routine
CDs with stories
Black out curtains
Kids hypnosis CD
Is there anything I am missing? I really do not know what to do anymore.

To be honest I used to hate the idea of TV before bed too but I've found my 2 seem to drift off with a DVD on if they lie in bad and watch it. His mind may just be unable to shut off, I know I have to tell myself a story before I can sleep otherwise I start going into horrible depressing thoughts. He is prob just overthinking about what he has done that day and perhaps has that kind of imagination that is hard to shut off. TV can be a welcome distraction from your own thoughts.

No ideas but watching. I've started putting 4 year old DD to bed super early (5.30 tonight) as it always takes her hours to go to sleep so at least this way she's asleep at a reasonable time. If she goes to bed at seven it'd be at least nine before she was asleep and she wakes at 6am regardless!