It's almost impossible to figure out some of those eBay listings. I don't think the people selling them know what they've got. I saw a couple "DXs" for sale, but the picture was clearly of a K3. Pay close attention to the pictures (if they're posting pictures of the actual Kindle), and ask lots of questions.
I'm looking to buy a DX too. Maybe you and I should get together, so we don't bid up the price on each other!
That's my advice.