re: How credible are the "Petrino to Auburn" rumors?

They're as credible as any rumors about the head coach of a highly-ranked P5 team accepting the same position at another P5 school in the third week of the season. That is to say, when Elvis, Tupac, and Nyarlathotep hold a joint press conference to announce it's a done deal and they'll be working on Gruden to Tennessee next, you can start to take such rumors seriously.

Where are you hearing these rumors, anyway? Sounds more like wish-fulfillment and angry post-game message board bitching than actual rumor-mongering.