I can't think it likely that any Tory Minister would want to take over right now. I also can't think of anyone of them who could do the job calmly and re-direct the party except J.R.M. and I think it's still impossible for a R.C. to be P.M. (someone will correct me if I'm wrong). My worry is that Gove seizes the chance, as the most senior and experienced, and I think he would be a real disaster.
So, I think (and hope) that Boris carries on for now - it's his mess and he needs to cope with it.