So the ability to put it in with a forklift or a crane would basically be a requirement unless you had it in several pieces that connect togethter. Further, this wouldn't reduce the cost or even make it a similar cost to the trimotor. To do this you would need to have some way to connect it directly to the battery to be able to use while charging. Alternatively, you could have a battery pack that would be designed to charge the truck in a traditional way, but that isn't at all Tesla is likely to do. Tesla wouldn't need to do this because EV's are becoming more and more popular and there are a couple companies that are working towards portable chargers that could give enough range to make it to a charger. It would be possible to make a really big one that could give you as much range as you want, but in my personal opinion, it would be a waste of money. If your day to day driving isn't enough to make a trimotor worth it, then don't a trimotor, because by the time the Cybertruck has been delievered to everyone that preordered it, we will probably see 2-3x the amount of chargers there are today. There will be a lot more Tesla Superchargers and destination chargers, as well as tons more chargers by other companies all over the world. There will probably be very few routes in the US and Canada that don't have a charger available.