I'm not following this thread closely, and don't know the SA API well, but have used a couple of the mail-parsing-related modules on CPAN. I don't know if it is a goal of SA developers to offer a "better, more robust" mail parser, but it'd be nice if there were one. The mail parsers I've tried do not seem to deal well with certain kinds of non-compliant mail messages -- which of course occur frequently in spam mail.
Long story short, is it out of the question to break out SA's mail parsing into a module that has a more generic, functional module name that would fit into the schema of some of the other mail parsers out there? I suppose that was the case in current releases where the SA mail parser was a sub-class of Mail::Audit? (I'm speaking from a very uninformed point of view, but hopefully the point is clear: to view the message parser as useful stand alone module in its own right, and possibly reenforce this by giving it a name and structure that fits in with existing mail parsing modules.)