I have a full static build of ffmpeg with all the options enabled (except ALSA sound, which was removed so that I could get it to compile). I thought I published in my "geekmaster kindle video player" thread. I have more than 4000 posts here -- hard to remember them all...
I was successfully able to play 1080p movies (with sound) on my K5 by using ffmpeg to play the network stream from the blender site, with video output piped to raw2gmv|gmplay, and another ffmpeg playing the same stream (in the background), with audio output piped to aplay.
I tested it on DX/DXG/K3/K4/K5. The K4/K5 can simultaneously transcode 1080p and play it smoothly, but on a K3 I had to transcode on a host PC and pipe that to the K3 with netcat (nc), or pre-encode it as a .gmv.gz file.
EDIT: I cannot find where I posted ffmpeg -- did I? Perhaps I did not get around to it yet. "Round tuits" are rare and easily misplaced.