Not that I'm aware of. Classes (ENPC, PALS, etc.) but not professional certs. Why don't you want to get the peds CCRN? If you're not caring for adults, you 'll have to let your CCRN adult lapse anyways.
Although obviously intended for pediatric emergency nurses, you might find the certification one that would interest you; particularly if you work in a facility without a pediatric ED, or one that processes patients rapidly through the ED to the PICU.
I have spoken with a few nurses that have obtained the CPEN, and all say that it is a fairly intensive examination. I have not, however, found anyone with both the CPEN and CCNR-P, so have not heard any comparison of the two.
CCRN-P is pretty much the gold standard for PICU certification. Even my friends who work on the floors say that CPN is very, very well-child focused. It's basic pediatric things that should arleady be in your brain in order to do PICU.