My ds is 3.5, he's been 100% dry in underpants during the day for months now, but is still sometimes wet at night. A few months ago, we were using 7th gen. disposables at night and he was wet every night. He would often wake up in a puddle, and that got old really fast--especially since he was still in our bed.
We went to a local cd store to find "night time unders" for him (at that point, he was insisting that he couldn't take his diaper off, even first thing in the morning, to use his potty). We picked out three different diapers, one all in one, and two pockets to try. We had immediate success with no more leaks, and spent time practicing how to take them off so that he could potty first thing in the morning. After a couple of weeks, he was beginning to be dry most nights, and he's now dry for a week or ten days at a time, but still having accidents sometimes at night.
I wish that I could tell you all of the names of the dipes that we tried, I know one of the pockets was a knickerknappies with something called a super do (hemp/microfiber insert that was leakproof, as long as the hemp side was facing out). The other pocket had snaps on both sides and was much looser like old school plastic pants, sort of, and we used the same super do thing to stuff it. I'm sorry I don't remember what it was, I just traded those in today to get more of the AIO, which is what has worked best for us. It's a BambooBaby, size large (supposedly 35-50 pounds), and I also use a hemp/cotton doubler in it. It's the only one that doesn't pinch or bind around his legs, it's super soft and very absorbent, has hook and loop closure, and they are holding up really well right now. My ds is about 36 pounds, I think, maybe more, and about 38" tall.
Good luck! A friend of mine is using 7th gen pull ups and finds they are way less absorbent (and more expensive) than the regular diapers. Oh, and the store we went to is also online, if you want to look at any of the stuff I could remember: zoombabygear.com, it's run by an mdc mama.
