Some of the "spam from yourself" appear to be from somewhere called Sund Design. However the owner of Sund claims that the emails are not coming from his company. He claims he has tracked the IP chain down to a Phone company in China and handed of the problem to the FBI!
I was able to use WHOIS to track one of mine through Amsterdam/Seville/Austria/Hungary before the chain broke, so it looks unlikely that it was originating in the USA. Maybe we should petition all the major ISPs to levy a posting charge on anyone who send more than say 20 emails a day?