Perhaps Apple will provide some means to burn that digital copy to media. The only problem with that is if Lion is like its predecessors it will require a dual layer burn - which are always iffy at best.

Here's where they might learn from Microsoft. MS provides Win 7 (all versions) as a digital download from their on line store. The download can be executed and then burned to a single layer DVD or 2 DVDs in the case of the Ultimate version. MS also mails out an optical version to the buyer.