I have found a media player that works from a portable drvie so far without modification. It is the VLC media player. I see right now though for someone to just unzip it to a portable drive it weighs in at 34.4 MB. But, it is just one of the many possibilities out there. There is also mplayer, which should work, but from the latest build, I don't see a gui present. But then again these are just some suggestions for possible media players.
Edit: This might not belong in the development section, but maybe in the General Discussion or Request apps areas.