According to a blurb over at FigureThingsout.com, the HP Touchpad is not sold out, a quick look at this time shows no results on their store page: stores.ebay.com/hewlettpackard. It appears that HP had scheduled a sale of the tablet device for today on their direct eBay store and sales have been running briskly ever since it started at 4pm PST.
From what I can see, there doesn’t appear to be any Touchpads left. I tried searching as wells as reviewing the categories and nothing shows up. However, don’t let this discourage you, there are still plenty for sale on eBay from other sellers wishing to unload their device as well as on Amazon.