Oh Dawg; just what we need -- another diesel-dummy truck driver.
You are correct, Captain, I would like to get away with simply switching the el-motor on and off with a five-dollar Ford starter relay. And the problem is the sudden lurch at the start, which could be "geared out" of it.
So far as I know, continuously variable transmissions rely on friction to transfer the power. I once owned a DAF automobile with V belts on variable diameter pulleys. And I currently use NuVinci hub-transmissions in a KSR vehicle.
I have seen a hand-built prototype of a variable transmission using chains and sprockets. The inventor was a retired tool-and-die machinist. The thing was a work of art to behold. But it relied on numerous small sprockets that continuously engaged and disangaged the chain. The problem, as I see it, was that once in a while the tip of a tooth would hit exactly on a roller of the chain, and there would be a hickup in the function. That was its Achilles Heel. But it was the closest I've seen yet to a low-friction CVT.
As you may know, I spend more time on Kinetic Sculpture Racing than on Burning Man. In KSR, we need as much as 2000% (two thousand percent) range in our gearing. Automobiles and bicycles have only around 300% spread. So I'm already in pursuit of such an ultra-wide-ratio transmission. (Most racers use several bicycle derailers in series, but they break a lot of chains.)
Recently, I have come up with a shifting system that may be my "holy grail" transmission. But it is still at the rough mockup stage.
If I perfect this, a variation of it might serve with electric power on the Playa. Two gears might be enough. Start in a "Granny" gear and let that wind out, then pop it into "High Range".
Also, the chain could have a spring-loaded tensioner ON THE PULL SIDE, to take some of the shock out.
But I just watched a perfectly good three-year-old 17 HP lawn tractor sell for $400,- on eBay, and I'm thinking that would be a better way to go -- just as you have pointed out before, so you may be pretty smart for a truck driver.