So my uncle recently gave me his top loader NES. He was one of those few people that actually bought one new back in the day to replace his fried toaster. When his SNES finally went out, I bought him a Retro Duo - he apparently owns the only Retro Duo in the world that works if you listen to people on this forum gripe.
The NES flashcarts are too damned expensive. You can look at those things and see $5 worth of parts on them. The only cartridge I have on hand is Super Mario 3 and that game is not nearly as exciting as we all remember.
So, I decide I'm gonna mod one of those Famicom multicarts into an NES. That means I've got to get one of these:

I'm 99% sure there's a few newer NES games with the Famicom adapter inside, but if you ask online you'll just get clobbered with the same copy pasta "black label" list.
And now, unfortunately, you enter the world of sleazy e-bay sellers. Some of them will be selling the 5 screw cases but can't quite bring themselves to show a decent pick of the connector pins. Or the game has been "cleaned inside and out" but no pic of the inside. They do, however, have auctions with loose adapters. So, yes, I'm pretty sure they're tossing worthless variants into 5 screw cases and hoping you'll take a $25 chance.
After a few 'cash in hand' offers were rejected, I ended up getting a copy of Gyromite for less than I had offered.


Yes, that game is just as bad as we all remembered.
Next I swiped some fan art version of Somari, put a beer in his hand, and printed my own shifty label:

And now we wait for yotsuya's slowboat package to arrive...