Updated information to anyone interested in a MR-1 single power source that works with international wall plugs, airplane plugs, car plugs.
The Kensington Universal 70w power adapter [http://us.kensington.com/html/10450.html] allows you to power notebooks, cell phones, pdas, iPods - and the MR-1 too - just changing its power tip. Different tips set automatically voltage and amperage according to the device.
As mentioned before, the issue is to find out what power tip works with the MR-1. Now I have the answer: the right one is the "P4", originally sold to power dell's Axim Pdas. I ordered one and everything is working nice.
Hope that will help someone...