It might be a longshot guess.
But possibly with the anticipation of the Magic Lantern success with the RAW video on the 5D3, people are buying them for some really 'cheap' high end video coming out soon?
I dunno if people buy things like this in anticipation of such functionality, but it is moving quite rapidly with ML and very successful so far....maybe people are buying them for that reason, and well, when demand goes up, so does price?
My $0.02,
cayenne