Where are you located? I have a few for sale/trade if your near Louisiana.
If not,just google your state + "video editing" or "video production" and email all of them,ALL-OF-THEM,no matter how small the studio. When I scored my 5 PVM's last week it was a very small studio with a handful of people. I'd also email all news stations in your state as well. Make sure to send the email to both the engineer and the general manager,ESPECIALLY the general manager. I've emailed probably 10 news stations in my state and I heard back from every GM,they'll at least reply with a yes/no or forward your message to someone at the station. But your best bet is local video editing places because they are usually privately owned and will probably hold on to their old equipment.
Also check your local computer or electronics recycling places. I've had a couple GM's at news stations here tell me that's where they bring their old equipment.
Edit: Dotmed is also a great place to score them. I purchased one from this guy and it arrived in good condition. It's a little cheaper than eBay and he's shipped a few so it should arrive safetly.
https://www.dotmed.com/listing/display-monitor/sony/pvm-20m2mdu/1886811