I've seen this list, though I can't speak to it's accuracy:
Ketamine Advocacy Network - Provider Directory
I did my ketamine infusion at George Washington Hospital with Dr. Chin. I know there is also ketamine infusions at Rush University Hospital in Chicago, though they only take self-pay (they will give you the paperwork to file with insurance). I never went to Rush, but I did speak with them and did not get a good feeling.
Hope this helps!