There are, unfortunately, numerous sedevacantist groups that disagree with each other. As indicated in the question, there are some that have tried to elect their own popes. There are also the Feeneyites, particularly associated with Most Holy Family Monastery, who deny the doctrines of baptism of desire (and, I believe, also of baptism of blood). For another viewpoint, one with which I agree, I strongly recommend that you look at some of the material at the web site http://www.traditionalmass.org/ and particularly the link "Key Issues". You might also listen to some of the sermons at http://www.traditionalcatholicsermons.org particularly those of Bishop Sanborn. (You'll be able to tell from the titles which ones are relevant to your question about sedevacantism and which ones are general Catholic doctrine).
One example of how these groups could see the issue resolving is Bishop Sanborn's position, which is essentially that the administrative structure of the Catholic Church continues, despite heresy, so that the modernist popes have valid elections (and the cardinals valid appointments) but are impeded from having the authority of the papacy by their lack of the Catholic faith. So the crisis would be ended if one of these popes were to abjure heresy and profess the Catholic faith (and, I suppose, receive ordination and episcopal consecration in traditional rites).
