In Toronto (vistek's main HQ) there are three major camera retailers. One of them, Aden Camera, is notoriously competitive in undercutting Vistek and it's smaller rival Henry's. I really have no clue, but this price could just reflect a recent price war between the three and not any official price recommdation from canon.
Vistek has more of the secondary gear to make your 5DM2 work better…and they probably figure they'll make money back on that. Any 5DM2 buyer is going to be a long-time investor in equipment and lenses… so selling the body for cheap is a wise move.
