I am actually extremely interested in practicing abroad (still trying to keep my options open however). I am currently living in Spain and have considered doing school here because it costs about $1000/yr. I'm still undecided, so I'm going to apply in the US for sure sure just in case. SO, I've been doing my homework! I've talked to numerous doctors here in many different fields. I've talked about both training in the US to practice in Spain, and training in Spain to practice in the US.
In my opinion, it is best to study where you are going to practice. BUT if you are unsure (like me!), the consensus is that US MDs are not going to have trouble getting a job anywhere in the world. Numerous med students and doctors alike have told me that if you have a US degree, you are not going to have much trouble getting a job in Spain. It may take some time to get your degree transferred through the government, though. I also have not confirmed this with any officials; it is just hearsay. The other way around, I've heard of people getting degrees in France, Italy, and Spain and doing their residencies in the US and then practicing in the US (one being an american born woman who is currently a neurosurgeon) . What I do know is that if you do your residency abroad it is unlikely that you can just come to the US without having to redo it.
Another thing to think about is debt. After accruing $150,000 of debt, and then moving to Spain, where the average doctor makes about $50,000 a year, you may find yourself with a bit of a problem... most Spaniards going through medical school have no debt to repay, which makes it more reasonable to deal with lower salaries.
This is basically what I have concluded in my search. This is all based on Europe, though. Things could be completely different in Asia. I don't know if you have connections with Asia and will be making a trip there or know people, but I'd say the best way to find out is to go talk to doctors there. I've been having a lot of cervical and arm pain, so I've been to the doctor a whole lot this year, so I've just been bringing it up to every new doctor I see and ask their opinions! They are glad to tell me what they think!