I think there are two things that are important in what you said.
1: Try waking up even earlier, even if it's earlier than you "need" to. Yes, I thought of this after reading your initial post when I was writing my own. I haven't *really* tried this. But there are some potentially fundamental issues with it which I'll go into in a moment.
2: Do "something" when you wake up. This is interesting and I think it's good advice, that I haven't really stuck to before.
So I think I can say it's possible you are right, since I haven't really given either of those methods a good try. Here are my issues and thoughts however (most are solvable, but not necessarily easily/cheaply/efficiently):
A: I find it phsyically very difficult and a very long process to wake up at almost any time of day. There are rare moments when I simply wake up almost instantly and it just somehow works, and I wish I could channel that at other times, but I can never do it at will. The brain state that controls me at wake time is a different one than one who might resolve something the night before, so even though I may have intention to just spring right out of bed and "do my thing", my morning brain puts a quick stop to that. I don't know quite how to circumvent that.
B: I have done the early morning thing for many years before now, so it's not a matter of time spent doing it. I do have some associations with early mornings - school and work of course. I'm not sure whether these are involved.
C: I also find that 8 or less hours of sleep is best. More than that almost always makes me more tired. 6-7 seems fine most of the time. Less can be an issue, but even then it's not usually major.
D: I do not drink coffee on a regular basis. I'd say about once a month. So lack of stimulants could be a big issue, even though you "only" drink once a day.
E: I don't watch TV, don't have a TV (watch movies, etc. on my computer though). When I wake up in the morning my time is purely functionally oriented. I take about 20 minutes to get ready for work so I wake up about 20 minutes before I have to go. That's it, no leisure time, no "getting other things done" time. I think of extra time awake before I *have* to be awake as wasted and unpleasant. This may tie into my poor time management. There are few tasks I can think of that would be genuinely productive for me to do in the morning that would be short enough to fit into a reasonable morning timeslot. I suppose all my forum checks could go there, that wouldn't be bad. A general morning 'net check. Exercise would be a good thing too...
F: The biggie: cold. It's almost always way colder than I like it to be any time before 10AM. The cold is a big part of what keeps me in bed where it is invariably warmer. I could get a space heater or something, but it would have to be on a timer. That too is feasible. It's not something I've ever tried. But my assumption is that if the outside temperature were pleasant or even warm, I'd be more inclined to get up. I simply detest the "shock" method of waking up - getting out of warm bed into cold air, splashing water on the face, taking a morning shower, etc. I don't do any of that because I don't like it.
So perhaps a lot of it comes down to attitude or ingrained habits. I don't really know. I do still feel that there are people just more naturally inclined toward day or night schedules, or somewhere in-between, and it is very hard for me to argue how well my natural sleep cycle tendency works in terms of time spent sleeping, awake time, ease of waking up, etc. 4AM to Noon seems to be my sweet spot...
I will consider your experiences and advice though. Somehow I doubt I will change anything fundamentally, but it could be interesting to essentially have my work day in the middle of my day - wake at 5, go to work at 9, return at 5, sleep at 10 or 11...