We may have to start labeling threads where we talk about sleep with the warning: Caution - mentions kids sleeping for many hours!!
My dd has only a handful of times in her life (she's 3 1/2) slept more than 9 1/2 - 10 hours at night (even in Guatemala) and didn't sleep more than two hours in a row the first 6 months she was home...I'm not sure I can stand hearing about any more kids that sleep (totally kidding!!)
Another possibility, because it can be an issue for us (since dd often does sleep okay now) is to check for constipation. That can be dd's issue and she doesn't express that she's in pain; it just wakes her up fully and she can't go back to sleep.
Susan
who dreams about sleeping past 5:30 am