That's a clever idea, and should do well for the Sliver Shivers decks. Unless you can get a real steal on Jittes, it might not be terribly profitable to recreate Rats' Nest though…

That's a great question. Most MtG packaging doesn't carry any real value- there's just not a large market for it (a few noteable exceptions include the fat pack deck boxes and the metal 'lunchbox' that Deckmasters came in). Generally when I refer to "packaging" value, that includes the fact that the deck is in a collector's condition (sealed).

That said, if you also have the printed inserts for the deck, that may add a touch of value as well for the collector, but it depends on the set. Many sets have had inserts that are descriptive of all of the theme decks (early decks had a little book, today's decks have a large folded insert), so a collector would really need only one. Other sets had distinct inserts specific to that particular deck, and in most cases the writeup of the deck is available online. It would be a niche of a niche that would give this consideration for purchase.

I'd be surprised if you'd get enough out of them to justify the time spent, but it would be interesting to see.