I can't find the thread at the moment, but I asked the same thing a few months ago, and I think the answer was 'no easy handset hack'.
90% of my DVDs are R2, so I ended up buying a UK R2 version for £190 to take to the US, where the exact same player in R1 form was about $180, under half price. The only advantage was I could pick up a spare battery for about £30.
The model number in the US was the same (FX810), so the FX815 may be a Canadian model, or an updated US model. The UK update to the FX810 is the FX850.
I think they are a good buy. The Panasonic players edge them out on PQ and screen size, but the 6 hour battery on the Sony cannot be beaten. I have two batteries, meaning I can watch 5 or 6 full films if needed on long flights/transfers. I would have needed several extra batteries for the Panasonic for that!