Watching some of the extra's on the 5 disc set of Blade Runner has brought up some interesting things, one scene cut from the film shows Deckard looking down at a photo of himself stood with who I can only assume is his wife, what's interesting is it's a similar picture to the one that Rachel shows to Deckard that she says is of her and her mother.
Both pictures take place on a white porched house front. I think this was another definite clue that Deckard is a replicant. Ridley Scott once said that he was a replicant in the film, yet on the commentary track he's more ambiguous about the situation. I'm sure this scene was removed for being to obvious.
Although the picture can still be seen in the scene when Deckard is sat at the piano, just before he has the dream about the unicorn.