Stumbled upon this write-up- SSTV from the Raspberry Pi camera, with direct RF synthesis, i.e. no outboard radio required, complete with motion detection and callsign overlay. Neat!
Low pass filter mandatory.
Nothing stopping this being adapted for HF SSB, in fact it would probably work better.
http://www.instructables.com/id/Raspberry-Pi-security-Slow-Scan-Television-Camera/