How does Margarito's KO of current Middleweight champ Sergio Martinez factor into today's boxing scene, and?

is a Pacquiao/Martinez fight at 160 lbs. a realistic possibility? The fight was over a decade ago, and obviously Martinez has improved dramatically since then beating the hard punching Kelly Pavlik and currently slated to take on Paul Williams again, but could Pacquiao possibly make that high a weight and still be competitive or is that pushing reality too far?