Can anyone point me to public (or share their personal) documentation on
the serial protocol and commands supported by the Baofeng UV-5r?

I'm interested in seeing if real time (or near real time) software
control of a UV-5r is practical.  Basically, I'd like to setup a
Raspberry Pi, some additional hardware [custom shield] and an Ethernet
connection [w/ PoE?] that could plug-n-play with a UV-5r that to provide
a remote [tower top?] back end to a soft [chirp based?] front end on my
Linux desktop or android smart phone.

 -- Tom Sayles
     KE4HET
    Fall City, Wa, USA