I agree we are all theorizing, but if the article you linked this morning is correct, we can throw out the idea that the state lab did not find DNA on the swabs. And you solved with that article the question of who knew to send the swabs to another lab.
"Two attorneys close to the investigation have told WRAL that the DNA samples have been sent to another laboratory for testing, but they were not able to say why -- whether it was for quality-control purposes or because Nifong was not satisfied with the results."
Yeah, it was a QC check. That's the ticket! :-)