From the Zune Insider blog:
What can hold up to 16,000 songs, or 20 hours of high definition video, or 25,000 pictures?
A Zune HD 64GB that’s what!
This morning we announced that starting April 12th you will be able to order a 64GB version Zune HD from Zune Originals for $349.99. All colors and custom etching will be available for you to create the ultimate Zune HD to your liking.
In addition to the new capacity, we are lowering the estimated retail price on the Zune HD 16GB to $199.99 and Zune HD 32GB to $269.99.
You may have also seen a little news around the forthcoming 4.5 firmware update, make sure to check out the Zune Insider podcast (video edition) this Friday. Matt and Jessica interview Nate Muller, project manager for the 4.5 firmware and get an inside look at the firmware update.