Unpacking Unpacked

Funny how, card-carrying grammar nag that I am, I had never really noticed this bit of broken language usage before:

“If you’re spring cleaning this weekend, start with your bookshelves – or maybe the boxes of books in your basement, still unpacked from the last move,” the Calgary Herald advised readers earlier this month.
See the problem in that quote? Hint: It’s not about cleaning priorities or Canadian punctuation. You might have hit the same speed bump in a New York Times Magazine story last February: ”It was dark when I slid off the bed, my feet landing on a duffel bag still unpacked from a recent trip.” Or in the Globe in January: ”Ensconced in a brownstone on Bay State Road, boxes of books and papers still unpacked from his office move there last summer, the man keeps a low profile these days.”
Unpacked, as you may or may not have noticed, does not actually mean ”unpacked” in any of these examples; it means the opposite, ”still not unpacked.” Obvious, once you focus on it, and yet the usage slips by editors and readers all the time; the Nexis news database is sprinkled with citations for ”still unpacked” all the way to 1978…

The piece goes on to helpfully point out that such usages are idiosyncratic haplologies, which is the dropping in English of one of two adjacents syllables that sound alike. In other words, unpacked in this usage really means “ununpacked”, but we drop one “un”.
In reading the Boston Globe piece I also discovered an excellent linguistic site for getting to the bottom of this sort of thing: Geoffrey Nunberg’s Language Log.