It is not inconceivable to see the other remaining states quickly passing bills to allow appointments
(assuming it isn't baked into the state constitution). I'm sure Oklahoma would make haste if the only ones left in Congress were Bernie Sanders, Liz Warren, Sherrod Brown, Nancy Pelosi and Donna Edwards. Likewise for Oregon if only Cruz, Paul, Gohmert, etc.
Also worth noting is that even among the states listed as having special elections for the senate, most still allow interim appointments, although with a plethora of caveats. When you factor that in, it seems like the vast majority of the states could at least somewhat quickly send a new Senator.
