Where are you from?
I go to the university of nebraska med center and Dr Hutchins is my endoscopist. I don't know if he's a nationally known doctor or not but that is all he does is endoscopic procedures. He doesn't see patients, he works in the hosptial and my hepatologist is the doc I see and when I have an EGD or ERCP Dr Hutchins does it.
Dr. Ronald Busuttil M.D., Ph.D, at UCLA Medical Center. (he's on the national geographic channel all the time for his ground breaking research.) i'm also lucky enough to have him as my doctor. i was a very complicated case.
you can read about him here.
http://www.surgery.medsch.ucla.edu/liverandpancreas/doctors_Busuttil.shtml
good luck,
kitson
The top three that I know of in the country are at University of Minnesota (Dr. Freeman), Indiana University (Dr. Sherman or Dr. Lehman) and the Medical Center at the U of NC, Dr. Peter Cotton.
I hope you have luck!