Nope. Surf over to Sony's website, there should be some news there. I'm afraid that player is scheduled for next year, though, so you don't expect to get it as a Christmas present.
Why do you insist on a hard drive based MP3 player? IMO flash RAM players are much better. They're (much) cheaper, solid state (i.e. they have no moving parts, you can safely carry them around and drop them and nothing will happen to them, nor will they skip part of the tune), lighter and smaller. My MP3 player, for example, is two times smaller than my palm (and I have a rather small palm), so light that I can barely feel it, it can play MP3 and wav (I think it can even play ogg, but I can't confirm that), it can record audio (it has a built-in microphone), Windows ME and XP detect it as a removable drive (which means you don't need any drivers for it), it comes with up to 224 MB built-in memory and with an additional compact flash memory card I can extend this up to 2224 MB! That much memory should be enough for about one full day of music - by the time you grow tired of it, you'll already be home and download additional music!
Basic model with 32 MB built in memory cost around 70$ one year ago, and by this time the price must have decreased significantly. Let's say it costs you 60$. You'll still have 240$ of your 300 to spend on a 1 GB compact flash card... Which you can use to transfer all kinds of data (did I mention you can use the player as a portable data storage device?), to plug into your camera or just take it apart to see what it looks like on the inside...