I've been searching, and I can't seem to find anything on nursing camps. Have you tried volunteering? I volunteered at MBMC (out in West County) for a few years, and it was actually really great. You could volunteer and shadow the nurses while you're there. I believe you have to be 16, though. You could volunteer at Barnes, Children's, Cardinal Glennon, St. Lukes, St. Anthonys, to name a few of the bigger hospitals in the area. Just call the hospital you're interested and ask about programs they may have where you could help out or shadow for the summer. Or maybe you could look into shadowing at Goldfarb or Chamberlain, the nursing schools? The best thing you can do is just pick a hospital/school you're interested and check their website.
Meaby you can try to volunteer as well, like at hospitals or nursing homes.
I found this, meaby it can help you out?