"Alternatively, you can get the digital version now, play right at midnight, overwrite your license with your CE when you pick it up, and then contact our support department. In most situations they'll be able to grant you a new standard key, which you can then give to a friend, or whatever. "This was taken from a post by Bashiok here (http://www.diablofans.com/blizz-tracker/topic/218979-any-way-for-ce-buyers-to-pre-install/#post24)
I would like to know if this is actually possible before making the purchase as I have a Collectors Edition being shipped sometime during or after the 15th and do not want to miss out on the midnight release. My plan is to buy the Digital edition to play at launch and when the CE arrives, upgrade my account and have my standard key either refunded or swapped for a fresh standard key to gift to someone.