Pediatric heme onc
I only know of speciality internship/fellowships--- heme/onc-- Boston Childrens, Emory University, Duke University and Texas Children are some. Have you googled or asked PNPs at your local hospital. It may take some time- but if you were to "wander" around and ask as many PNPs at the local Children's hospital you may get information.

When you are ready to look for a job I would like to warn you NOT to use a recruiter! You do not need one! PNPs are in great demand! I unfortunately learned this the hard way and was suckered in by a woman recruiter from Colorado. She cheated me and owes me money. My experience was frustrating, sad and now expensive!

Keep the faith, and congratulations on your accomplishments.