I think those resale prices are towards the upper end of the resale market. And that they may, in part, be driven by still-tight supplies of the iPad 2.
That said, however, I think the strong resale price, and an existence of a market for year-old iPads, speaks volumes about the strength of the original design. That, out of the box, and in conjunction with the software updates Apple has put out, the original iPad is an incredible piece of kit - still outclassing the various Xooms, Playbooks, and Galaxy Tabs that have come along to challenge it. It also says, to me, that many consumers aren't that interested in the (limited) camera functionality that seems to be the biggest "feature" added to the iPad 2.
The strong resale market for iPads - and indeed virtually all Apple products - is part of the reason they hold the strong market position that they do. If you can buy an iPad or Mac, and a year or so later turn around and resell it for 80% of what you paid for it, its a strong incentive to buy Apple - as opposed to the numerous "me too" products, for which resale is limited.
