It really surprises me that Archie isn't interested (you wonder if things weren't so hot right now if he'd be interested). It seemed like he was kind of looking to this job as a career move. Plus, he's a great choice.
Tressel taking it would be bad overall. First, if it meant he would leave the coaching position, that would suck for obvious reasons. Second, at a school the size of OSU, it would be really tough to handle the football team and all that it requires along with the AD job.
Based on what I read I was kind of hoping that the Maryland AD, Yow, would be interested. Hopefully there's someone good out there that will be uncovered during the search. Many of us probably wouldn't have put Tressel first on the list for the HC job, and look what he's done.