My little guy is like that as well. He is now old enough that he will play for a while on his own, so I can occasionally do other things. But when it comes time for nap/bed, I'm stuck there beside him. We go to bed at 8:30-9:00. Sometimes it takes me a while to fall asleep. If I'm tired in the early AM when he wakes up, I sleep with him during the morning nap. Otherwise, I read. I've read several books in the past few months! On the occasions when I've tried to get him to sleep without me, he never lasts more than half an hour. (He normally wakes at half an hour, and then he usually goes right back to sleep if I'm there, especially if my eyes are closed). When he falls asleep in-arms, he will wake up if put down. But if I'm right there and nurse him, he'll go back to sleep. I tried a sling for him when he was about a week old, and he hated it. He has occasionally slept in a Kozy carrier, but only when I was doing a lot of walking (around the mall or something like that). Like some of the other posters, I've just accepted -for now- that this is how my son sleeps, and there isn't much I can do about it. I'd rather have him well-rested than do other things. Clearly this system won't work if the difficult sleeper is DC #2 or beyond (a prospect which makes me nervous...).
I keep waiting for that maturity that everyone talks about to kick in.