Here are some videos of Sterylite with ankles.
Here is a side view. You can see the motion of the ankle servos from the side. All the servos are doing at this point is trying to keep the feet level.
Here are some videos of the six motor gate of Sterylite 6000. The sliced broomstick feet work great on grass. You can see that the back feet tend to drag, which is a problem for climbing obstacles.
This is a side view of my six motor quad walking on grass. You can see that it is pretty fast, particularly when you consider this is a relatively large robot. Forward speed is not an issue.
The lurching gate does cause a lot of mechanical stress.
A view of Sterylite where you can see all legs at least a little, if you couldn't imagine it.
Clearing 2" obstacles (as required):
This is the path where I would get stuck a lot with six motors:
My son decided to call this robot fluffy.
Here is a brief example of the robot using sonar for navigation. Fluffy uses sonar and an internal compass as part of my home navigation project.