The progress on this guy has been kind of slow, and mostly in software. The current status is that I have the video streaming from camera to the web browser working, and I resolved the issue with noise on the serial line that made it impossible for the robot to walk properly (it turned out to be some kernel logs still being output to the serial). There still seems to be some problem either with the leg inverse kinematics, or the walking algorithm, as the legs move a little strange -- this requires further investigation.
As for the twin brother, I'm trying to program it entirely in Arduino, so that it's the cheapest quadruped robot around. If that works, I will add a basic "laser tag" gun to it and try to talk some friends into making their own version, so that we can have a cheap version of the Mech Warfare battles. It will probably be a separate project, though.