I like that -- however how do you deal with the fact that spammers can be all over the planet?
I think it was McAfee that did some reasearch that shows that something like 10 or so banks that keep funding these operations. Even if you managed to shut down all of them, all that will change is that the money is going to go underground.
You also have another issue. There's people making money spamming, and people making money providing spamming services by renting out access to their botnets. I think those raking in the big bucks are the ones that sell their spamming services to the gullible.
The international nature of the thing makes it dang hard. They only need to reach one spam haven to survive.
In the meantime, the only thing I personally have control over is my network. So yeah, to keep my end users happy, I spend money on a spam filtering gateway. I'm not happy about it ... since there's always some false positives (even if it has gotten better), but that's all I have as far as tools go. What you propose is fine and dandy, but right now ... individual admins don't have that much choice in the matter.
This being said -- Email should be regulated, like HAM radio is. If you had some kind of regulatory environment that requires some kind of "licensing" to operate Email servers with identifiers, I think it could also help out because it implies ALL mail senders would have to conform to regulations. And it has the benefit of decentralization. World-wide, HAM radio operators only have to follow local laws controlling them.
I don't know if in the "real world" it would work ... but having MTA operators be responsible for what leaves their servers and networks would probably be a step in the right direction.