It sounds like you need to build a "device update pipeline". Get a pro and use it until VNext comes out and either gift or sell (eBay?) the "old" tablet to the next person in your chain. If VNext doesn't come out too quickly, you should be able to pull the value you need from the original purchase.
This may work for cars, but I think consumer electronics generally devalue too quickly for that not to waste a lot of money.