I wouldn't be surprised at all if the MX is capable of fully and autonomously hitching a Tesla "smart" trailer. To be more specific, I believe that the car will fully maneuver itself into place once you're within a few feet, will raise/lower itself onto a trailer hitch with Air Suspension (possibly with assistance from the "smart" trailer), and make the necessary wireless connections for brake lights and signals, along with retracting supports to ready itself for travel. The "smart" Tesla trailer would be something produced most likely by a supplier, would have the ability to self-lock and may have proprietary additional connections to replace the chains or other safeguards commonly on single-hitch trailers. It likely would run self-contained off a small combination of solar and a battery. While this is pure speculation, I think there are a few very important factors that would drive Elon to create such a system: 1) Supercharging. At most superchargers, you would need to un-hitch a trailer to charge or wait for a pull-in spot to become available, and hitch back up afterwards. That'd add considerable time and inconvenience to roadtripping with a trailer. This process makes sense because Elon designed a complex snake-arm that'd be effective in real-world automated charging for multiple types of vehicles, sizes, and suspension heights--I think it's very clear that he wants a MX owner to be able to eventually park his/her vehicle, press a button, and the car will automatically unhitch, charge itself, then hitch up by the time you're done with dinner. I imagine Elon wants every Tesla owner to be able to autonomously charge once reaching a supercharger eventually, no matter what vehicle they drive. With current tech, simply automated hitching/unhitching would considerably speed up every supercharger visit. 2) It's well-known Musk used female focus groups in designing the MX. I can only imagine that storage is very important to this group, along with the ability to carry passengers. I think Musk saw an amazing opportunity here and went for it. 3) We already know that even the MS is planned to be able to self-drive on private property, park itself, and do a few other neat autonomous functions. Maneuvering to hitch a trailer seems super easy for a computer to pull off by comparison. Technology that helps the robo-snake find the charge port likely could lend itself to the car finding a trailer hitch (wireless receiver in the hitch plus camera imagery). 4) Hitching a trailer is a pain in the rear. It's even more excruciating when doing it solo. Musk tends to build vehicles that, first and foremost, suit him and his multiple children particularly well. Musk also has been single off and on. Hitching a trailer with just yourself is much more annoying than hitching with a partner. Connecting the dots, one day he probably thought "I can design a rocket that lands itself upright--why the hell am I hitching this thing myself?!", and hence this feature came into being. 5) It seems like Tesla would do, reinvent something mundane from 100+ year old tech (door handles, a front trunk, gull wing doors) and turn it into something 21st century. Speculate away!