I still haven't found or heard anything about Columbia. I hope they put one there soon. I think Boonville or Kingdom City would probably be easy for Tesla to set up, but I really don't want to see this happen unless they do both. I think there are enough people who periodically commute to Columbia from KC and St. Louis that you really want the Supercharger to be in Columbia; if you pick either Boonville or Kingdom City (and not both), you screw over half of those people. I know Columbia doesn't look all that big on the map, but it has the University of Missouri, several smaller colleges, multiple large hospitals, and insurance company hubs. I myself regularly make trips to Columbia from KC for my work.
It wouldn't be as bad a problem if Columbia had good destination charging options, but it doesn't. There is only a single L2 public charger in the entire town of 100K plus people, and I still haven't even found it (can someone give an address or GPS coordinates of this mysterious charger?)