22 kw generac cost $6000 and labor to install approx $1500 which is $7500 generator, materials and labor.

My company has installed in the last 5 years approximately 2500 units price usually is determined by gas supply and electrical runs

Worth every dime you spend when you need it. Good hot meal and shower.

If I have a Kubota tractor, that is in excellent condition, could I just buy the generator base unit and use the tractor, to run the pto on it? What would that cost?

22kw pto, $4,000+/-, 200amp transfer switch, $800+/-, some installation $$$(seems that's debatable), probably cheaper than what's mentioned above

yep I know it's a ripoff but not too uncommon. These heating and A/C companies charge plenty of folks that much in labor to install a split unit, and they can do it in half a day. Iam like you, I would just do it myself.