If you've already got a Linux system, the Debian openvpn package is under 1 MB and at 50 kb/s would take under 3 minutes to download. I don't know if openvpn in particular is suitable for people who are trying to evade their government, but would whatever features it is missing add substantially more size?
Of course then you get into needing software to decode the more advanced encodings; maybe start with a voice transmission explaining in plain language how to decode the first layer, which gives you a program that can decode the second layer, or something.
Starting to sound like an interesting project.
