Agreed, this would be my choice as well. While my first inclination would be to configure the mail server to launch a perl script when a particular address received mail, having a client read the mail gives you a lot of flexibility regarding where and when the perl script is executed.
Of course, it's up to you to determine things like the "correct" subject header and proper formatting of the message. But other than that it seems like a relatively simple deal.
PS & FYI, I love Log::Dispatch
for writing messages.