Help for parents of early wakers?

I've been getting several emails from parents who have toddlers waking up really early (like 5 am). The kids are obviously still tired, but can't get back to sleep or stay asleep. Then they're cranky for the rest of the day.

I'm sure many of us have gone through this on limited occasions (it happened in my house yesterday, which is why I didn't post and was foggy at work all day), but having it happen morning after morning would be truly demoralizing.

Here are the things I've suggested:

  • Blackout shades on the windows. You can buy actual blackout shades, or you can buy blackout material at a fabric store, or even just heavy drapery cloth and make your own.
  • Mess around with bedtime. Sometimes it seems like the kids are just in the wrong place in the sleep cycle, and that's why they wake up. So switching the starting sleep time around might alleviate the problem. (I also think it may be sort of the same effect whacking the side of the TV has to get it to stop fuzzing out, but that's just me.) As counter-intuitive as it sounds, I'd start with bumping the bedtime earlier, unless you've already got a 7 pm bedtime, in which I'd try 8 pm. (FWIW, it seems to me just from hearing people talk that most kids have a sleep-time sweet spot between 7 and 8 pm, so if you're totally up in the air I'd start with 7 and see where it gets you.)
  • Check out the naps. How old is your kid? Most kids older than 18 months are down to one nap a day, in the early afternoon. If your toddler is still taking two naps, the early waking might be part of trying to drop the second nap. Messing around with that might give you some more information.
  • Look at what your kid's eating. I think diet problems (including bad reactions to artificial things or acids, and reflux) usually manifest themselves earlier in the night (waking up screaming an hour after going to bed is a classic sign of reflux or too much acid, for example). But you never know. Anything that's causing stress on a kid's system can make the difference between being able to go back to sleep after the slight arousal of finishing one sleep cycle, and if they're having a tummy problem of any sort, that could do it.
  • "Psychological" causes. I didn't know what else to call it, but some kids go through a monster phase, when they wake up and are scared of random things or of monsters or of being alone. You could definitely try some kind of monster-scarer or other comfort object (I think you'll have better success with something you get specifically to scare away the bad things than just trying to use an old comfort object) and explain that it will help them get back to sleep in the middle of the night and keep them safe.

But if none of this is working, what do you guys recommend? Like everything else in parenting, you could just wait it out. But if your child is desperately tired, and you can barely function at work, you need to  get everyone sleeping longer ASAP.

Does anyone want to offer solutions, suggestions, anecdotes, or commiseration?