Installation costs are a big part of current solar farms, and a big part of that is the labour to assemble frames, do up all the bolts, connect all the wires, etc.
If we could make a single truck drive along at 0.5 mph leaving a trail of installed panels, it would really make installation far cheaper. The truck could take as 'input' a container of solar panels with the necessary legs and supports, maybe even concrete bases, all ready to go, shipped direct from the factory.
Other components could be combined to save costs too - for example, the inverter could be built into the panels. The panel frame and the mounting frame could be combined to save weight and assembly time. In a big line of panels, only the end ones have high mechanical wind loads, so middle ones could use far more lightweight plastic supports.
Then creation of a 1 acre solar farm could be as little as a couple of days work for 2 people driving the truck.