Our DS9, not ADHD, was much the same way, but not anymore. At ages 5-6, we started letting him get up when it was light out (a killer in the summertime) and go downstairs to play quietly - no tv or video games or computer (he always has to ask before using those anyway). It took an awful lot of crankiness from me to get him to remember the "quietly" part, but eventually he did. By age 7 he could play for a couple hours, and once I was able to sleep through the occasional outburst (read: explosion noise), I made a deal with him that at 8:00 he can turn on his CD player at a low volume (he usually chooses a "book on tape" type) even if we are still sleeping.
This has worked out wonderfully, and now I can even get an hour to myself *after* I wake up! He is usually so engrossed in whatever he is playing that he doesn't even realize right away that I'm up and I have to remind him to come up for breakfast. Seriously, sometimes I don't even see him until 9:30!
I think part of the key was my intolerance (I'm not proud of it, but it worked) and the other part was allowing him the CDs - I really think the hum of a human voice gave him all the comfort/engagement he needed.
Oh, by the way, all of this applies to weekends only. During the week we are all up and moving at dreadfully early times.
This is us with DS6... now if I could just get DD4 to NOT come to me every five seconds when she gets up to ask me when I'm getting up, I'd be good.
