Nobody went to Gamereproductions.com and list all those NES repro games.
I think the discussion was more about licensed NES games, otherwise the NWC carts, the 6 in 1 games, the Panesian games and others like that would be the clear hardest to find. NES reproduction carts are kind of under the same category, though you can usually order those anytime, so they aren't really that hard to get a hold of.