Below are the LEGO beam hole counts, which are 1 unit longer than the linkage's bar lengths simulated below.
Below is how this LEGO approximation compares to Jansen's holy numbers for Strandbeest's linkage (scaled so that the crank's length=3)
This LEGO approximation of Strandbeest was found with this simulator, where you can create your own version of the linkage, and find other approximations of Strandbeest.
As shown below, Strandbeest's speed and turning can be smoothed by adding feet that slide or rotate described here.
We'll try to get some frame instructions up soon, but for now here's the basic layout of each frame side. Both sides of the frame are the same, just flipped around.
Frame triangles are critical for making strong frames for walkers, but LEGO's integer-based beam lengths can make it difficult to find diagonal beams of the correct length. You can find other ideas for creating triangle-based frames with LEGO beams in this blog post.
Below is the spacing for the legs
Be sure to add the below outer frame so that the outer axle is connected to the Center of Rotation!
With the undercarriage mounting it's pretty easy to swap between the battery box and EV3 brick
The Mindstorms medium motors are longer than LEGO's power function medium motors, so they had to be mounted on top of the 40 tooth gears.
Make 8 of the following legs
Below is one idea for making a strong center crank of length 6:
The above gray axles have a length of 5
More ideas for managing Dead Points can be found here.