While backpacking last year, I toured Angkor Hospital for Children in Siem Reap, Cambodia. It's basically a free hospital for the people of Siem Reap and surrounding provinces. They do take a very limited number of medical students, but based on the information on the site I don't think it's equivalent to a rotation here in terms of what medical students get to do (I'm not a med student, so perhaps I'm wrong). I also don't really know how you would go about setting it up. The main website is http://angkorhospital.org and I think this link has specific info regarding medical students http://angkorhospital.org/help_vol_medical.php?state=1#MedStu
Another hospital group to check out is the Kantha Bopha ones, located in Cambodia. I think there are 4 or 5 hospitals in Phnom Penh and Siem Reap, set up by a Swiss pediatrician. He gives cello performances at Jayavarman VII hospital in Siem Reap every Saturday. If you google "Beatocello", information will come up. I'm not sure if they take medical students or not, but it couldn't hurt to do some investigating.
I currently live in Vietnam and sadly cannot offer any advice about the hospitals here. I'm pretty sure GWU and UWisc have programs here, so maybe you could go through one of those universities.
