I looked into it, and if I'm not mistaken, the NYU one was only open to NYU students (I dont know why they advertise then). I think I remember hearing of one at UConn? Don't quote me on any of this...I tried looking it up again and couldn't find the info on the internships yet.
As of last summer, the only true externships around that accepted students from other schools were RIC and Cinci (to the best of my knowledge). I had some communication w/ the Indiana program, but I got the feeling that its more of an informal program and they seem to usually take Indiana students.
To any students looking for PM&R experience b/w M1-M2:
In addition to the above 2 programs, I would highly rec. contacting a local PM&R residency to see if it would be possible to get involved w/ a research project and/or some shadowing in several different areas of PM&R. I really stress the importance of several different areas, as most students don't realize how broad the opportunities are in the field.
I second that. Both the Rehab hospital affiliated with my school and Hopkins were receptive to my requests to shadow and also helped me out with finding research and funding as well. Every physiatrist I have interacted with has been eager to show me what the field is all about and has been extremely helpful.