Skin Thunderbird with a Mail look
Apparently someone by the name of "Riz" has a love-hate relationship with Apple's Mail, for Riz has gone and created a pretty darn accurate Mail theme for Mozilla's Thunderbird.
While I don't have a copy of Thunderbird to test this, it seems the look, feel and most of the icons are all present, offering a bit of a home away from home if you prefer Thunderbird's functionality, yet miss Mail's good looks.
[via Hawk Wings]