You make a very good point, in that there is a filament sensor in both the print head and also in each AMS Lite filament station in order to handle this right now if someone were to design an 8-to-1 merge hub similar to the current 4-to-1 hub, and then place that hub on the side or back of the printer. Since the printer currently pulls any of the 4 filaments out just enough to clear the 4-filament hub on the print head, adding a hub that mixes filaments from 2 AMS Lites would require the AMS motors to pull their filaments back to a greater distance to clear both hubs (adding a little to the print time), and then you could have a 8-to-1 hub mounted where the manual filament spool entrance is, with a single bowden tube going from there to the print head. Like the X1C with AMS, the filaments would get pulled back further away from the print head, a standard distance to clear the filament past the hub merge point. Of course, this would require a firmware upgrade (or knowing the secret code to unlock it if it’s already in the current firmware as a hidden feature).