If you don't want to be bored, you'll want a level 1 trauma hospital. So I did a quick search on level 1 trauma on Google and found this. I think Bellevue is NYU and Elmhurst is Mt Sinai. I can't speak for how good the electives are though:

The Official New York City website (www.nyc.gov) for ?level 1
trauma?, and found the following hospitals.

Jacobi Medical Center (in The Bronx)
http://www.nyc.gov/html/hhc/jacobi/html ... enter.html

Elmhurst Hospital Center (in Queens)
http://www.nyc.gov/html/hhc/html/elmhurst.html

Harlem Hospital Center (in Harlem)
http://www.nyc.gov/html/hhc/html/harlem1.html

Bellevue Hospital Center (in Manhattan)
http://www.nyc.gov/html/hhc/bellevue/ht ... _dept.html

A map of all The New York City Health and Hospitals Corporation facilities in
New York (including the above four centers) can be found at]http://www.nyc.gov/html/hhc/html/map.html[/url]

I'm not sure if this helps, but it's a start I guess.