Hello,
For those aspiring Pluggable Transports authors out there, I've recently written a simple library that handles the Tor Pluggable Transport Configuration protocol. The idea is for this library to be the C/C++ equivalent to pyptlib (and maybe more, depending on how much time I have to work on it).
The code is available at: https://github.com/Yawning/liballium
It still needs more documentation, but all of the use cases are covered by a reasonably well commented example (examples/ptcfg_example.c).
Questions, comments, feedback all appreciated.