I'm really intrigued by him, but from what I've been reading, he's been talked about as a HC candidate, so would he take a DC job? This article for example, states that if Tom Gamble (49ers Dir. Player Personal) landed a GM job, he would likely take Tomsula as a HC. Luckily the teams interested in Gamble already hired different GMs. LINK
Tomsula makes sense as a head coach candidate. He has primarily been a defensive line coach, but he gained some coordinator and head coaching experience in NFL Europe. Tomsula has "only" been coaching since 1998, but something about him strikes me as head coaching material. He commands the respect of players, and with the right staff supporting him, I have a hunch he could be an excellent head coach.
He's my #1 right now. Hopefully he would be interested in the job.