After rooting around the FCS, I found some old data for randomly named "Empire Nobles" along with "Noble Processions". These appeared to function as glorified shopping trips, with the noble being under heavy guard.
I've made a mod that adds this back into the game. I recommend using it alongside my "Samurai Lords" mod for even more variety when travelling in UC territory. Both are entirely lore friendly
Noble Processions: https://steamcommunity.com/sharedfiles ... 2403049985
Samurai Lords: https://steamcommunity.com/sharedfiles/ ... 2287038661