Update 2012-06-22

Update 2012-06-22: BDan and Alexander Berger have convinced me I was wrong to write off chains. At least right now there are more possible chains than kidneys to start them, and they can be quite long. My updated estimate is that this gets you a 3x multiplier on the value of a donated kidney, bringing the $400 charity equivalent to $1200. Which is still less than the $10-$100K at which I think I would sell a kidney, but substantially higher.