I don't know if it's actually been attempted, but in his book, Business at the Speed of Thought, Bill Gates indicated that soft drink machines could be rigged to do quite a few things, including sending an order in when they got down to a certain level and raising or lowering the prices depending on the temperature. It's been a while since I read his book, but I believe he did mention individual pricing structure depending on what people are willing to pay. It's already done on cars and houses, as well as the loans for each of these, and most large appliances have a built in fudge factor. I got Best Buy to knock $200 off of a stove. It's just that on small ticket items it really hasn't made any sense to dicker over the price.
Would also mention that it's rampant in wholesale. That's one of the big reasons Walmart can sell stuff for less than a small businessman can buy it for.