Hey, this is my first post on anandtech; though I have been using the website for about 5 years now.
I also had the same question about the xbox power supply issues. I sold an xbox to someone in the hague and needed to have a system that would run in the US as well.
As far as I have been able to find the stock xbox power supply does not have the ability to switch between 220 and 110 v; though I have been able to locate a relatively cheap replacement power supply that will do the trick.
Power Supply sold on Divineo
As near as I can tell it does require you to open the box to change the power, which sort of sucks, but that is not a huge issue. I have not tried this myself yet. I'm still waiting for mine to come in.
It says "Work on all xbox version! (1.0 to 1.5).
DOES NOT WORK ON XBOX v1.6." However after further investigation, I have found a site,
llamma, that says that the type of connector that power supply has, the AT style connector, will only work with v 1.0 and 1.1. So I don't what the discrepency is about and I am too lazy to open my xbox right now to find out.
Hope this helps