AmeriJet out of MIA flys the plane for Zero G. They actually have a paragragh in their OPS Specs for zero g flight.
The reason the few 727s still fly corporate is they are so cheap. Not to operate but to own. I've seen dash 7 and 9 200s for around 800,000 USD and dash 15 and 17 for 1.1 million. At that price, what you are really buying is a 500 mph engine stand because the engines are worth 250k-300k mid time. If you are only flying a couple times a month it doesn't cost you anything but ramp fees while it sits. You can even buy insurance by the day for when it does fly.