I'm not saying to go to TV stations. That's not probably going to work. I'm saying that if you have TV stations in your area then some of these things exist or at least existed in your area. They go to auction, they go to employees, they go on Craigslist, eBay, whatever. TV stations, video services, things like that, these are the only places that bought these things originally. No consumer wanted a 19" display in 1998 with no tuner and a price tag of $1800, just the commercial market.
Keep looking, check Craigslist more than anything, be prepaired to drive if you live in BFE. If you live in a city don't be afraid to drive *to* BFE. Be creative in your search terms. Most people in the real world don't use terms like "PVM". Don't limit yourselves to Sony, I have a JVC that is amazing (quite possibly it's a rebadge Sony, I don't know).