Nice progress. Yes, kindlevncviewer's CLI switches are horribly under-documented. They accept everything that libvncclient can handle. My guess was that x11vnc's ZRLE encoding was broken (didn't bother to debug), so I specified an encoding on CLI: "-encodings copyrect,raw" for kindlevncviewer. For all possible switches see here:
http://libvncserver.sourceforge.net/...44eb97d2356475
Errm, are you using Xfbdev, als the command lines you quoted indicate? Because the setup I imagined was using Xvfb...