As of yesterday you can now purchase the ZuneHD 64GB from Microsoft’s ZuneOriginals online store for $349.99 without any customization. We’re told they sold out quickly the first time around, and that’s why the option to purchase it was removed a few weeks ago.
It’s also important to note that it has not returned in every color, silver has not returned just yet. Also it looks like the Zune 120, and all flash Zunes are gone.