? There are a couple of scripts in there for finding e-mail in files. I know because I wrote them. They're not perfect, and I'm not sure if they'll be faster or slower than anything you've already tried, but it might be a place to start.
(I will warn you, though, I'm a Network Admin, not a Perl Programmer, so the code reflects the, um, "utilitarian" nature of the effort and the speed with which I needed a solution.)