I got mine replaced...
First of all, there are two different issues. One is the stuff that is coming up from the cushion underneath the seats, that one is the "wipe it off or vacuum it" problem. The other is the "spooge stain" which is the one I had.
Long story on how I got mine replaced made short:
Dealership believed me that it wasn't a stain that I made, but a new program required them to send digital pictures to FordMoCo for any cosmetic repairs. Ford refused to repair the seat covers and responded with "Stains not covered under warranty."
SVT was of little assistance (They can not moderate between a customer and a dealership or Ford). They recommended I call an area rep or something of the sort. Scheduled with the dealership to bring the car back when the area guy was around. He said it was a stain, handed me some sooperdooper 3m Cleaning stuff that he said would resolve the problem. He wiped down the drivers seat, and while it was wet, it looked great. I then took the car back to work, and cleaned both seats with the cleaner and a fingernail brush as advised. As soon as it dried, the stains were back.
Met again with zone rep about a week later, he overrode the decision by Ford on what he called a "Customer Satisfaction" claim. Basically - Ford, SVT, and the zone rep refused to admit that there was an issue. All parties claimed that this was the first they had heard of it. However, my dealership had already done a replacement on another SVTF with the same problem, before they were bound into this digital imaging thing.
So, now... I have new seat covers, no signs of the same problem, and am a happy person. If SVT Claims that they haven't heard of this... call them on it, there are more than a few of us who have contacted them about it. I spoke to a person at SVT named Rob about the issue on several occasions, if he doesn't remember that I'd be floored; because I got a little pissed off at him.
Hope that helps!