I am not yet a CNA, but am also interested in working in pediatrics. Here is what I have found:
Labor and delivery units of hospitals sometimes employ CNAs. Usually this is in larger or busier hospitals. Some Birthing Centers will also utilize CNAs.
The NICU/PICU in my area employs CNAs, but I don't think this is the case in a lot of other places. Most prefer RN's in this position.
Pedriatic CNAs may also find work in children's hospitals or pediatric offices.
And lastly, there's the Pediatric Home Care option.
I really hope to be lucky enough to find employment in one these fields. I realize it will be difficult to get into pediatrics just starting, but I'm trying to be optimistic. I'm hoping that recommendation letters and volunteering at a children's hospital will be helpful.