The big problem that I see is it will take huge batteries to make big suv's into an ev that has a 200 mile range. Part of the reason all the ev's are small cars or sedans like the Tesla's is you need an aero shape to be decently efficient. So it's easier to make a small effient car have a decent range.
The physics suggest that an ev is about 3x as effient as an ic engine, but when you are talking less than 20 mpg (like a f150), 3x that is only a 60 mpge. That is roughly 2 m/kWh. To get a 200 mile range a 100kwh battery would be needed. A simple 6 kWh L2 charger may not cut it anymore.
Teslas aren't exactly the most efficient. From the numbers I've seen, electric motors are closer to four times more efficient than ICE on average. The ideal would be some sort of Atkinson cycle engine, such as the one found in the Toyota Prius, which can be as much as 36-37% efficient at converting potential chemical energy. However, the vast majority of ICE are only about 20% efficient. Further, electric motors maintain their efficiency advantage over a wider range of driving conditions. Also, due to the mechanical requirements, ICE vehicles tend to have far worse aerodynamics than an equivalent EV. Finally, ICE vehicles suffer far more mechanical losses due to clutches, gearboxes, etc.
While I'll admit that range extenders are a good option for heavy duty trucks, I'm not convinced that those range extenders need to be ICE. Fuel cells might be a much better option for a number of reasons. As was already mentioned, ICE are not very efficient, and even basic NG/LPG fuel cells have as high as 80% efficiency, and they can run off of the same pressure flows as the gas lines into your home.
Regardless, based on what I've seen so far with the Bolt EV, I'd be surprised if a small truck or SUV saw less than 3 mi/kWh in normal driving. That would be 180 miles of range out of a 60 kWh battery pack. Given the size and mass constraints of current battery technology, I would say that the reasonable cutoff point at which increased capacity isn't justifiable is ~120 kWh. Two Bolt EV battery packs would easily fit under a 1/2 to 3/4 ton pickup, and that would result in over 120 kWh of usable capacity with a total weight of about 1,800 lbs. Even if your 2 mi/kWh estimate was right (and I think it is unreasonably low), you'd see 240 miles of range out of a charge. DC fast charging would make it usable even for long trips. If it was as inefficient as you predict (again, unlikely), the current L2 probably wouldn't be reasonable. That is why Tesla provides an 80 A L2 charging option.