I don't know how I ever missed this one when I searched for email clients. That looks like such a breath of fresh air: the download is under 10MB and it even supports GPG.
I second that! Thank you very much for the link. Looks like the perfect lightweight and powerful mail client. And the fact that it stores each mail in its own file is absolutely bombastic. I guess I can finally sync my mail on different machines using my cloud storage as the sync back-end.