Seeing the cost of the servos so cheap, and the parts so easily duplicated, I'm very interested to build one... however, I see that those are the easy parts. I don't see what mpu you're using, what source, calibration effort, etc. Care to expand?
The mechanics were indeed the easier part of the design. I'm currently going forward using a an Arduino (the pro micro to be precise) and two Adafruit PCA9685 breakouts (https://www.adafruit.com/product/815) to control the motors. I'm designing a custom library for the Octopod control that can be found here (https://github.com/kelliott121/Octopod). It's currently a work in progress, but so far I have gotten both the Servo and Joint classes working. I'm working my way upwards and hope to soon have a full Inverse/Forward Kinematics engine with programmable gates.