I think I have picked up one or two MW pirates in the last few years. As others have mentioned, it is a tough band antenna-wise, both for the broadcaster and listener.
Radio Celestial used to be very active from NYC on 1710, and before them Lubavitcher Radio. Is Celestial still on?
A few years ago, there was a semi local pirate that would appear on 1610 between Thanksgiving and New Years, with ID's as WEDG The Wedge, playing non stop Christmas music. I heard it for a few years in a row, but nothing of the last year or two.
I can certainly add a new forum dedicated to MW pirate loggings/etc, that's a good idea.
Celestial has been off the air for a few years. They were always getting the knock, but I don't know if that's the reason they're gone? It seems to me there was something about the transmitter going pfft.
Speaking of Lubavitcher, the rumor when they left the air is they sold the transmitter to Celestial. As the hobby is full of half truths when it comes to operational details, for very good reasons, it's hard to know what is true and what isn't.