At first I tried using larger, standard sized, servos.
However my supply was not capable of delivering enough current to all servos at the same time on 5V. It would always brownout and completly reboot. If I only used one leg and hooked up it's servos to the supply one after the other it worked, but that was no acceptable condition.
So I decided to give it up... For now.
I still uploaded some pictures and an .stl file of the complete robot to admire it's beauty. This first on is the blue/black one.