In the future we will not only be able to play Day of Defeat: Source in the european World War II scene and with americans versus wehrmacht but also in the pacific theatre.
A group of modders have started to work on a modification to Day of Defeat: Source where the battles takes place in the pacific theatre and with americans versus the japanese force. They are making a whole new class, japanese, with new models and weapons as well as new maps and much more.
There are currently not too much information available about this mod, called Day of Defeat: Source Pacific Theatre, but they write on their website ( http://www.dodpacific.com/ ) that we can expect more media and ingame videos to be released soon.
Links:
http://www.dodpacific.com/
http://www.team-zeropoint.net/scenenews/617/