I have to put in my vote for BumGenius pocket diapers. I have been using them on my 12 month old son since he was 2 weeks old (don't use them before the cord falls off). I LOVE that I have never had to buy a new size, so even though these might be a bit more, they are soooo worth it!
I didn't think that I would get my husband on board, but he took to them really well since he didn't have to mess with covers or snaps. The pockets are also great because I was able to use the newborn inserts when he was smaller, and double when he went through a heavy wetting period. The only leaks I have gotten are when daycare puts him in a jumper wet and his pants are all bunched up around his upper thighs - they will wick. But, if daycare doesn't put him in there wet, there are no issues.
My son also had some chunky thighs and there was never a fit issue. There is a learning curve to get them tight enough though, so if they leak at first, reevaluate how you put them on. :) Also, they are a tad bulkier than disposable, so for pants, you may have to go up a size, and the torso is a bit longer. Now that my son is older, it doesn't affect the clothing size as much.
Cottonbabies.com
weebunz.com - I thought buying them in dozens was a great deal