sew your own diapers

So I have started to think about trying to get rid of as much PUL as I can.  Don't get me wrong, I think the stuff is great and works incredibly well.  I just have noticed that my little guy gets heat rash quite easily and think that PUL, being a non-breathable fabric and synthetic to boot, may be the culprit.  So I was thinking that, as long as I am on a role getting wool interlock and knitting more longies and diaper covers, I might try my hand at a knitted wet bag (?).  Has anyone seen a pattern for one?  I admittedly found one pattern online, but I was hoping for something a little heftier.  Perhaps I will just make up my own pattern.  One that is lined (the outside being from a bulky yarn and the inner a worsted weight).  It could be sewn together with a zipper.

Then again, I may just take the easy route and get some extra wool interlock and sew one.  Just have to finish up a few projects first...

Well, if anyone sees a good knitting pattern, I'm game to try it out. I certainly have the yarn to spare.

any luck??  i haven't seen anything . . .