There was a dealer from Calgary at the recent "HuntFest" show in Edmonton who had a camoflage system that used a large light-weight mirror. The videos looked effective but the product seemed a little bulky (like a folding table with a mylar finish on top).
google "The Shadow Shield" I think that's it.
PS - Having looked at the Ghostblind website, it appears to be a similar concept (using mirrors to hide a person) but looks more "hunter-friendly" with its multiple panels, camoflaged back and straps for easy carrying.