Hello, I need a list of bulk email list providers who will engage in
CPA (cost per acquisition/cost per lead) advertising and/or charge
0.50 or less CPM.

These must be full-service providers, that I can send the creative to,
they pull the names, and they take care of sending the email.  (I will
host all creatives.)

Also, I require the provider to be 100% opt-in and Spam-free, and to
be able to document this in case of questions.

Please do not simply send me the names of random advertisers on Google
or other engines.  I want to pay for a *pre-screened* list that meets
the criterion above.  This may require calls or emails to be sent to
make sure they qualify.  Ideally, I'd like 5-10 providers that match.

Some good starting points:

http://dmoz.org/Computers/Internet/E-mail/Marketing/
http://dmoz.org/Business/Marketing_and_Advertising/Internet_Marketing/Marketing_Services/Opt-In_Email/

Thanks!