According to capedwonder.com, those covers are not he official covers. Just mock ups. Here is what he said:
The Latest DVD News...12 September 2006
Many fans have e-mailed me recently with very specific and worthwhile questions regarding the upcoming DVD releases, in particular the Ultimate Superman Collector's Edition box set. I'm afraid I have no more answers that what are presently circulating around the World Wide Web. Despite my inquiries, Warner Bros. is keeping a very tight lid on everything right now.
I did received this message from Warner Home Video yesterday, 11 September 2006:
"Unfortunately, the box art in the trailer for the Donner Cut is not correct so they are fixing it. Regarding The Christopher Reeve Superman Collection, we have not received approved finalized artwork for this. Unfortunately, your fans are just going to have to wait regarding the Ultimate box set as we don't have any news as yet. We will make sure you are part of the initial announce when we do announce."
Warner also told me that the artwork that has been showing up on the World Wide Web for the Ultimate box set was not authorized for release, so they are asking websites to take it down immediately. I've already done so. The art you have seen is definitely an early concept from my discussions with WHV, and likely will change a few times before it is "officially" released (whenever the heck that is!).