The original didn't work with the servos I had on hand, and I wanted to be able to add more articulation and improve bits without having to start over from scratch. Thus: the Modular Hexapod.

The dovetail tongue and groove design was inspired by the Simple Spool System for Makerbot http://www.thingiverse.com/derivative:5005 I wanted to be able to switch out parts as I improve them and to avoid absolute positioning.

Video of my first configuration in action: http://www.flickr.com/photos/moleofproduction/5318014248/

More videos w/ creepiness cranked up to 11:
http://www.flickr.com/photos/moleofproduction/5331316152/
http://www.flickr.com/photos/moleofproduction/5330707869/
http://www.flickr.com/photos/moleofproduction/5331321724/

I used the nifty Pololu Micro Maestro x6 servo controller and 4 AAA batteries to get things moving.

Skull attachment adapted from: http://www.thingiverse.com/thing:4378 printed w/ MakerGear .25 nozzle.

Print the base, a set of servo skirts, and whatever servo arms, limbs, and couplings fit your configuration. If the skirts don't fit your servos, or the couplings don't fit your bearings, it's easy to make a new set in Sketchup. I'll upload my .skp after I've cleaned it up a bit.

To make a 3-servo Hexapod like mine, you need:
1x modhex1.stl, Base
2x modhex2.stl, Left servo arm
2x modhex3.stl, Right servo arm
1x modhex4.stl, Middle servo skirt
2x modhex5.stl, Rear servo skirts
2x modhex6.stl & 2x modhex7.stl, Forward and rear legs
1x modhex8.stl & 2x modhex9.stl, Middle legs
1x modhex11.stl, forward bearing bracket
1x modhex13.stl, Middle servo arm
4x modhex14.stl & 2x modhex10.stl, Limb coupling