Fred:

Go with the Nigerian Scammers idea and copyright might not be an issue.

Here's why:

First, they have to prove the fake name that appears on the emails you publish is them. Then, they have to file a complaint that you are using their emails - with the fake names - to make a profit and doing so without their written permission.

The moment they do those two things, THEY are in DEEP trouble because THEY are, in effect, raising their hand and admitting to fraud - or at least attempted fraud. And they are NOT going to do that. - Unless they are really dumb.

Michael Ross