In
TubeX, the script looks at the fle extension and chooses the player accordingly. For iPhones, files wth 'qt' (Quicktime) extension would use the Qucktime player provided with the script.
It works very well if you host your own clips and have different formats available, but most sponsor hosted clips are flvs, so you're back where you started if you used sponsor clips. (although there are sponsors which will give you clips in multiple formats.
The major hurdle in all this is Apple. They decided they do not want flash on the iPhone, with YouTube being the exception. An alll in one player would be a dream come true, but getting around all the licensing BS would be difficult.