I think we've established that if there is an overpriced board out there and someone buys it; that someone is you.I'd pay $500-600 no sweat for a nice one right now if you have a second...

Joking aside I think you're missing the point. Just because someone is dumb enough to pay a high price for a PCB one time (like $1000 for a Punisher) doesn't make that the market price, similarly just because someone gets a good deal (like $350 for a Punisher) doesn't make that the market price either. The truth lies somewhere in the middle.
What is is the average price they sold for over the last 6 months? that's the real "fair market value".
With that said, if you list a PCB for sale and people who are actively looking for that game don't buy it right away, then it's above fair market value, because those people are the ones who know what recent sale prices are and are likely to be buy it for a price at or below what they've seen other recent sales complete at.
I can tell you that CPS1.5 games have been on my radar for a bit and they're selling on YAJ for around $450 for non-working and 600-900 for working depending on the game and the included art, this based on 20-30 listings I've seen over the past few months. But I've also found that SHMUPs and Beat-Em Ups tend to sell for much higher prices on YAJ than they do on USA eBay, which we also know typically has higher sales prices than KLOV.
I think the only one I've seen actually sell for over 1000 was a C&D with full arts and an original box.