At the Milwaukee camping show in February I ran into an old colleague of mine who is retired. He is a driver now and essentially says it is up to him to pick and choose his jobs. The local dealerships have his number, they call and agree on a price ( a lot depends on the price of gas) and away he goes.
He'll tow all types. I've seen his one-ton dually towing 40 foot toyhaulers and 17 ft hybrids. He enjoys it.
I'm certain there are larger companies with contract drivers, but I get the impression that many dealerships use this type of individual.
DW, 3 Kids and our Goldens
2012 Shamrock 233S
2008 Toyota Sequoia 5.7L 4WD