dogleg mail routing

one of the ways I deal with being blocked by idiot blacklists is to 
route through a friend's mail server.  That server may be going away 
which means there's a few domains I can't send e-mail to any more.

It occurs to me that we could create a relatively abuse resistance ad 
hoc network of dogleg routers for mail if each message had not one but 
two stamps.  One stamp would be for the destination address and the 
other would be for the mail server.

Now I haven't thought this out much but I just want to float the idea 
and see how we can weaken it to minimize load on the message originator 
and strengthen it against spammers.

I also want to minimize the workload on the dogleg router administrator 
as well.

just thinking aloud.

---eric

-- 
Question: What's the difference between the Vietnam War and the Iraq War?
Answer: George W. Bush had a plan to get out of the Vietnam War.