Hi Mojo:
You might want to look at Ripken Academy which is at Aberdeen Maryland.
While on business a couple of years ago in NJ, I stopped by at a few local indoor training facilities in the evenings. Places like this must offer summer camps, I would guess.
There is a thread just below, asking about youth Elite camps, as well.
I am hoping to take my son to camps at Clemson and Tennessee in a year or so. They appear to be very good camps but, I am pretty sure they will hold fairly strictly to their age limits.
Cheers,
D