Granted, this is pie in the sky and would require a lot of things to happen beforehand, but what if ALL of the well-known traditional bishops united to elect a pope? How would that conclave be any less legitimate than all of the Novus Ordo "bishops" uniting to elect a "pope"?
Regarding Papal elections, the authority remains in the Constitution
Vacante Sede Apostolica, promulgated by Pius X, in 1904. See # 17.
"the right to elect the Roman Pontiff belongs solely and exclusively to the Cardinals of the Holy Roman Church". All others being absolutely excluded whatsoever ecclesiastical or lay position they may have.
Even if you wanted to argue as Clemens Maria said, that this Decree belongs to the realm of Disciplinary Law and could potentially be reversible, who could reverse it?
Only a legitimate Pope has the authority necessary to abrogate a disciplinary Constitution of a previous Pope. In this case, Pius X, an unquestionable legitimate successor of St. Peter.
I know this is not what you or I want to hear, but it is what it is. Even conclavists must admit it, and they can become rather pathetic really fast (think Pope Michael). Reality does not go away just because we wish to. We, Catholic laywomen, personally don't need to be "waiting" for anything. What we need to do is saving our souls on a daily basis.