Apple MagSafe Airline Adapter, it might do the trick. Apple MagSafe Airline Adapter - Apple Store (U.S.)
From the listing you linked: There may be automotive versions available, I'm not sure. But you can certainly purchase a small automotive dc power inverter (just make sure it's rather for at least as many watts as your adapter [I think the largest Apple MagSafe is 65W]). Then just plug your MagSafe into that.
It can be moded sorry for not researching prior to posting. http://pangea.stanford.edu/~schmitt/magsafe/ Posted from my iPhone via the Tapatalk app.
I have a 200 watt 12 to 240/120 volt power inverter I plug into the cigarette lighter, then plug charger into that. Feri
I got an adapter made by power+ for my 2007 15 inch macbook pro. Works incredibly well, and is made really well/not just rigged together. Oh and it goes for less than $40. http://www.amazon.com/dp/product/B002U1ZPL6?tag=priuschatcom-20
Does the technology package have the 120V inverter built-in? I think models of Toyota for Japanese market have the Inverter built-in (this was the change made in response to last year earthquake).