From the Aug 27 Weekly Update:

"To those of you who had already purchased a Digital Collector’s Edition prior to that announcement, we promised that we’d have some additional information for you:

'If you purchased the existing Digital Collector’s Edition, and you already owned Destiny and both expansion packs, we’ll have some additional information for you soon.'

We haven’t forgotten about you. We know who you are, and we’ve kept a list. We’ve also identified what we’re going to give you for your awesome early purchase. Unfortunately, it’s stuff that won’t be available immediately at launch. The use of the word “stuff” here is regrettably vague, but we think you’ll be pretty excited once you learn the details.

We’ll deliver those details as soon as humanly possible. Thanks again for being patient."