There is an IETF working group which aim is to work on those issues. As mailing-lists are opened to anybody, you can follow their progress or even give suggestions. More info on http://ietf.org/html.charters/marid-charter.html

Description of Working Group:

It would be useful for those maintaining domains and networks
to be able to specify that individual hosts or nodes are authorized
to act as MTAs for messages sent from those domains or networks.
This working group will develop a DNS-based mechanism for
storing and distributing information associated with that
authorization.

The primary current use case for this facility is to allow recipient
MTAs to confirm that peer MTAs' actions are authorized by
specific domains or networks. This will help combat a certain
class of domain forgery common in spam. The solution chosen,
however, should be generally useful for others which might
check this authorization data. [...]

-- 
Brent Frère

Private e-mail:  Brent@BFrere.net

Postal address: 5, rue de Mamer
                L-8280 Kehlen
                Grand-Duchy of Luxembourg
                European Union

Mobile: +352-021/29.05.98
Fax:    +352-26.30.05.96
Home:   +352-307.341
URL:    http://BFrere.net