I've been reading your posts for quite some time, and am finally joining in.
My DS is 18.5 mo, and I can count on one hand the number of times he has slept more than 10 hrs overnight in his lifetime. Until about a month ago, he had been sleeping 8p.m. to 6 p.m., napping anywhere between 1- 2hrs at around noon. He falls asleep easily, quickly, and by himself, in his own crib, and sleeps through the night. Recently, he started spending one night a week at grandparents house, where he sleeps on a mattress on the floor in their room. Since then, he's been waking up earlier and earlier -- we haven't made it past 5:15 or so in more than 4 weeks. The 5 am wake-ups are hard, but I'm also worried about the total amount of sleep he gets in a day (ave. 11 to 12 hrs in 24). I'm contemplating trying an earlier bedtime, but that's a scary thought when we're battling such early wakings. I'd be worth it, though, if he would sleep more hours overnight. For those who have had success with earlier bedtimes extending overnight sleep, do you think it would work for a baby that's never really slept more than 10 hrs.