pluggable transport ideas
i just leave some ideas here for brainstorming and discussion: protocols that could be used:
bgp and other routing protocols: its important for the infrastructure and was even used to enforce censorship. thus it might be too hot to touch for censors.
various streaming protocols: internet radio or video streaming provides an unsuspicious data flow.
rdp, rfb(vnc) and teamviewer: a censor might hesitate to block the tech support for their goverment and industry
industrial, telemetry and military protocols(scada,lonworks,...):might be too hot to touch as well
mail: pop3, smpt, imap or send mails over legit mail servers
ventrillo, teamspak and mumble: same as streaming
others: ntp sql radius hadoop mongodb