I know a bit about this. People are quite frequently publicly executed or sent to a concentration camp (kwaliso) by the Bowibu for listening to radios, watching foreign DVDs, or making an international phone call.
Many people have tunable radios, the smaller the better, despite the fact that the price can be very high- your and your families lives or bribes.
Here is a image which gives you an idea of the situation.
http://nkinusa.org/board.php?board=nk52&command=body&no=6&
If any of you hams have good ideas for ways to make HF AM receivers smaller (really small) or more inconspicuous, AND cheap, they need help. We could all wait another 50 years and the regime will just keep on killing people in the most horrible situation imaginable, or we can brainstorm how to make good radios smaller and cheaper and maybe help change something. This is not rocket science. There is just this big need for fresh ideas. They need every idea they can get.
Make a note of this situation and maybe you will have an idea.
How about a regenerative circuit? Back in the 1930s, American radio manufacturers like Emerson made two tube regen radios that for the era were small and cheap. In the 50s there were the "boy's radios" made by the Japanese and targeted at American teens, that were also regen designs. Those were sold under inconspicuous names like "Americana" to get the radios past Mom and Dad, many of who "remembered Pearl Harbor" and refused to let anything from Japan in their houses. The laws back then were more lax than today on putting country of manufacture on products, and the boy's radios sometimes lacked ANY mention at all of Japan, on the radio or the packaging.
Anyway, I would think that a small regenerative radio, which could be made with two transistors, hooked to the classic anti-jamming antenna that was developed by the Americans for Russian use, might be just what the North Koreans need. I should also note that in Nazi Europe, headphones were usually used by the resistance so that the local Gestapo wouldn't be tipped off. The radios used now in NK seem to use speakers, which require more power and put the user at risk of being discovered. I would think that a regen radio driving a single headphone that would be hidden in the user's ear (like the "earbuds" used in the US) would require less power, be smaller, and be less easy for the secret police to detect.
Edit: Christofero's link shows an NK civilian listening to a radio under a blanket late at night, so I guess they DO use speakers. They need to use earbuds, definitely.