Sure the Director accounts and big guns can do it but just how do they get Stereo sound on Youtube?

Looks to me like for a while they were not reprocessing certain FLV files, but now it looks like they are reprocessing all files and making them mono. I've not done much testing, so I'm not sure, but it seems to be the case.

If you want to be able to upload versions of your video that are left untouched, YouTube is not the place for that.

Try blip.tv, they leave the original version of your file "as is," they also transcode to Flash (with 64KHz mono audio) if the original is not Flash, however, you can make your own high-quality Flash Version with stereo audio and upload it as an alternative format file and it will be left alone. Users visiting blip can choose among the alternative formats, and you can then use the various formats in an embedded Flash player on your own site as you see fit.