"I want to attach an automotive alternator via a belt to generate AC volts to run an inverter...."
Your post is a bit confusing, by definition, inverters convert DC current to AC current, so you don't want AC Volts to run an inverter, IMHO.
I'm gonna GUESS you want a 120 Volt AC power source?
If that's what you want, I think CC dealers sold PTO driven AC generators, for sure DEERE did.
Here's a link to a thread posted by someone who fabricated one.