I got iTunes 5.0.1 two weeks ago!! Check it out (see attachment).
Strange thing. I was trying to update iTunes 5.0.0 to 5.0.1 via Software Update. I had a network issue, and it disconnected, but I don't think that was an issue. I tried again and it was fine...except I had an error trying to verify:
Software Update could not expand Package correctly.
After repairing permissions, I tried again, but the same thing. After googling for a bit, I came up with a number of possibilities, including a missing tar file, false receipts, or a missing link to my tmp folder.
What it actually was, I discovered, in my console log, was that I already had it! i checked in my packages folder, since I normally keep them. In there was an iTunesX.pkg which I used to update from 4.9 to 5.0.0. I remember it saying "version 5.0.1" and it being strange. I removed it from the packages, and tried Software Update again - sure enough, it downloaded and expanded fine.
you can see the info from each of the packages I have that they are both version 5.0.1, but one is from two weeks ago, approximately the time of 5.0.0, and the other one from yesterday (real 5.0.1). Having said that, though, both files are identtical in size, so maybe they're actually the same file, and I somehow broke it during my disconnection, making it have a version and file size of the new one, but keeping the creation and modification date of the old one. I dunno - does anyone have the original 5.0.0 package they can verify with?
I hope this helps anyone else having problems.