Some, ummm, interesting theories to be sure. Looks like I've found the answer though: It's for a vent fan to remove moisture and help keep the seat cool. Part of a full-boat option package in high-end Porsche and MB sport models.

Here's a few pics from a Porsche turbo of the $3000 set (familiar lookin' seat, eh?):







If I come across some more detailed photos or info of the vent fan setup I'll post them, as it might be an easy mod for those interested.