In 'A Plan For Spam', PG talks about how the spam of the future will have to be decidedly unspammy to get past bayesian filters.
I think I just got one:
"Am Vincent Cheng, GBS, JP Chairman of the Hong Kong and Shanghai Banking Corporation Limited.I have a sensitive, confidential brief and I ask for your partnership in.Get back to me for more information."
It has amazingly good grammar (for a spam message).
Of course, the from/reply-to still gives it away:
from: Vincent Cheng <ctruitt79@sbcglobal.net>
reply-to: chengmr.vincent65@yahoo.com.hk