So I'm probably being overly optimistic but let me live in my dream world for a bit.  

  DS currently sleeps 3 hour stretches most nights and that pretty much maxes out the KL0's we use most of the time even with some extra absorbancy added.  I have some OS pocket dipes for when he is big enough but that will be awhile still so I am looking for something to use in the meantime once he starts sleeping 4-5 hour stretches (I know, I know - but I can hope!).  Any recommendations on a good sized pocket diaper or something else that will keep him dry for a bit longer?  Should I try prefolds plus a doubler or insert?  Currently the cover is holding everything in but he is SOAKED when we change him so I know it's only a matter of time.  Thanks!                
Re: Being Optimistic
The KCK pattern has a sized-pocket version available, if you happen to know anyone who makes them...
There are numerous different types of KCK diapers. The most popular (at least in my shop) is the KCK One, which is a one-size pattern. It works best at 10#+. However, there are several other "sized" (as opposed to one-size) KCK patterns available that go from newborn all the way to toddler. The difference between the sized patterns and the one-size patterns is that sized diapers are adjustable width-wise, but not in the rise.
I hope this makes sense. Feel free to convo me anytime.