The Golem Project is an example of Mobility Evolution, interesting and possible if you start in the middle!
Videos of the evolutionary systems are provided and the starting 200 are evolved over 600 to 800 generations.
It illustrates robotic evolution guided by considerable academic support. The demonstrations are far from convincing, but I have an open mind; perhaps one of the neglected bars will evolve without support from academia.
Note that the starting point has: rules, a brain, and reproductive capabilities. Not exactly starting from GreyGoo. There is a page called EvolutionistsStartInTheMiddle which makes this point.